Lonely Mountain

The Lonely Mountain gets its name from the fact the nearest mountain range was hundreds of miles away. It provides a habitat for ravens and thrushes.
Given the proximity of Dale to the Lonely Mountain, we can expect the elites in Dale to benefit from the contracts there and the trade in the minerals. Dwarves, given their presentation as extremely greedy, will also likely take the deal as well. Granted, dwarves are also known for being a little racist it seems, so that is a problem. The result is that I see the dwarven leadership letting a few people in to run the mining operations in exchange for massive royalties. They will accept limited foreign intervention in exchange for greater power and wealth. Meanwhile the rest of society will suffer poverty and be easily incited to revolutionary violence.
Now, I suspect that most of the logic of the Lonely Mountain's Foreign policy would be the same as the Iron Hills. The main difference being that they would probably not have as strong of a trading relationship with the Easterlings. Nor is the majority of their income "strategic" resources like iron. The result is Mirkwood would have less incentive to attack. To me, the Easterlings would move to be the main threat. Not to say the elves would magically start to like the dwarves in the Lonely Mountain. But the animosity would be more rooted in history and mutual distrust rather than strategic issues.
On one hand, this means that Mirkwood and the Lonely Mountain would probably not directly go to war. But we have to remember that the Iron Hills are really close by the Lonely Mountain and (assumed to be) ruled by the same king. Therefore, the possible attack against the Iron Hills by Mirkwood would likely lead to the Lonely Mountain jumping in. This would lead to a relief force being sent to the Iron Hills. Once the siege is broken, a combined force would attack Mirkwood. Or, more likely, Mirkwood would recognize the threat and be deterred from aggression.
Not to say that there would not be tensions between the realms. The Lonely Mountain would need its fuel. This would mean wood. Some of this demand for wood would be reduced through slavery to mine coal. But I highly doubt that this would reduce demand for wood to zero. This means Mirkwood would be the main source. Obviously the elves would not be too happy with the destruction of their homes to literally fuel dwarven industry. Tensions would build. I would not be surprised if the elves of Mirkwood intentionally leave the dwarves to their fate when Smaug attacks to eliminate this threat without war. This would lead to all out war once the Linely Mountain is reestablished. Or the elves would outright go to war in the Battle of Five Armies to stop the return of that threat. Either way, the dislike between realms would be on the brink. I would not be surprised that by the time of the War of the Ring, things would have hit a boiling point in some form. It might be possible that this conflict would have been handled via flower wars for a period of time.
Now, the Lonely Mountain is one of the main dwarven kingdoms. It was by far the richest in the books - even after being destroyed and rebuilt. This means that it would likely be the most well known for using the economic hitman model to achieve its ends. Who would be targeted? Well, I doubt Rohan would be seen as having too much to offer or exploit. But the Easterlings are close and would have one of the most ineffecient economies in Middle Earth. One that would prove highly profitable if it could be forced to change. I suspect that the Lonely Mountain would use it economic power to keep the Easterlings dependent and under control. Prisoners of war from the internal Easterling wars could be used to fuel dwarven slavery. As the structural adjustment programs are enforced and slowly begin to turn a profit for the dwarves, the products of those would flow to the Lonely Mountain as well.
But the proud and militaristic Easterlings would not like the apparently "soft" and materialistic dwarves hiding behind Foriegn Direct Investment to control Easterling Affairs. Hence another source of conflict. Possible also flower wars between the Easterlings and Dwarves. Sauron would probably keep his minions in line, preferring to unleash the full power of the Easterlings at the most beneficial period. So full scale war would probably not break out until the War of the Ring. But when it comes to that, the Easterlings would attack eagerly. But there is the threat that their resistance would be enough that the dwarves would be forced to go through the full cycle. They might be forced to conduct a full scale invasion to ensure the Easterlings uphold their end of the deal.
Lastly there is Gondor. Its fortunes are on the decline. This means a former superpower overburdened. Revenues would be declining. But spending would have to rise to meet the rising challenges of more active Corsairs, Mordor, Easterlings and Southrons. Gondor would be easy prey. Especially with its mountains possibly as good sources of mining operations. Plus, there is the possibility of the declining fortunes of elites that could allow for land grabs. Not to mention criminals and debtors that can be exported as slaves. The seeming weakness of the Gondorian leadership and other more pressing concerns suggests they would probably be close to totally passive in the arraingement. Individual leaders would probably resist then get overthrown via covert operations. But things would probably not go much further.
One interesting thing here is that the War of the Ring would probably solidify Dwarven power over Gondor for a time. First, the Lonely Mountain would recognize the threat of Mordor, the Southrons and Corsairs to dwarven investments. Therefore, they would probably provide conditional aid to Gondor. This aid would be to cover the purchase of arms from the Lonely Mountain for Gondorian troops. Some of it would probably be provided to hire dwarven mercenaries to plug gaps in Gondor's southern border wall. The money paid by Gondor to cover Aragorn's raid on Umbar would likely also have come from dwarven aid. Then there is the reconstruction money. But that discussion will come later.

Demographics

Mainly dwarves with a small community of men nearby in dale/laketown.

Government

The Lonely Mountain would represent the most "pure" form of dwarven government.

Defences

This orientation creates an almost ideal defensive position. The two ridges create a perfect kill zone. Any force attempting to take the mountain would have to breach the well fortified main gate while being attacked from both sides by forces entrenched in a natural fort. And I have to admit – the gate is one of Middle Earth’s most impressive. After years of disrepair, a dragon attack and only 20 days to prepare for attack, Thorin’s party was able to hold against an army of orcs estimated to be between 10 and 25 thousand. Granted, there was about 2,000 troops on the flanking hills, but if the gate doesn’t hold then those are irrelevant. As Thorin’s 14 person group was the only force manning the gate, that means they took the main brunt of a direct assault with a ratio of between 714:1 to 1,786:1.

Infrastructure

Due to its location, it also had a major road that served as a trade link between the eastern and western dwarf lands. This added to its power and wealth. A major river forms from water flowing off the Lonely Mountain. This forms a trade link between it, Lake-town, Mirkwood and eventually the Sea of Rhun.

Assets

The Lonely Mountain is actually the main force in the context of the War of the Rings. The other kingdoms were either poorer or destroyed. In the later periods of the history of Middle Earth, The Lonely Mountain was the main Dwarven kingdom, with most of its wealth and population. Based on studies looking into the wealth of Smaug, we can assume that the Lonely Mountain has a wealth of $8.6 billion to $870 billion. But more common appears to be more mid range estimates of between $54.1 billion and $61 billion.

History

The dwarves who settled here were originally refugees who fled Moria. They thrived here, able to equal or surpass the wealth of Moria. Their residents eventually branched out into the Grey Mountains. But their wealth provoked the War of Dragons and Dwarves. These Grey Mountain colonies were wiped out and the survivors fled back home to the Lonely mountain.
Many years after this war, Smaug attacked the Lonely Mountain, wiping it and Dale out. All the dwarves were killed or fled. Human survivors formed the community of Laketown. When Thoin and Company arrived, Bilbo broke in and stole a cup. Smaug was enraged, blamed Laketown and destroyed it. Fortunately, Bard killed him in the process. The fall out led to the battle of Five Armies.
After that, Dale and the Lonely Mountain became prosperous again. This posed a threat to Mordor. Its superior defenses and location meat that Mordor would struggle to get its armies to the Misty Mountains. So Sauron attempted to tempt the King Under the Mountain with control over Moria and 3 of the 7 dwarven Rings of Power. When Dain refused to aid Sauron in finding the One Ring, Easterlings attacked in the Battle of Dale.

Architecture

The construction is all underground. Huge caverns and grand halls appear to form the majority of rooms. Long and slender bridges connect the various regions. It, like Moria, had a secret back door that was extremely difficult to get to or even see.

Geography

The Lonely Mountain is about 10 miles in diameter and 3,500 feet tall. It is located 20 miles north of Lake Town. The top is snow covered even in spring. There is a central core area under which it appears most of the settled areas are, with six ridges radiating out from it. The ruins of Dale and the main gate are located on the southern side in the valley formed by two of those ridges. A guardroom is located at the end of the western of these ridges called Ravenhill. Most of the inhabited regions appear to be between the front gate and the core peak.

Natural Resources

Pine was the main timber found in the area. Massive lodes of gems and gold are its hallmark.

Type

Large city

Population

At its height it had a solid 60,000 residents. Gimli was the son of one of Thorin's party members and represented the Lonely Mountain at the Coucil of Elrond.

Owning Organization

Common Dwarf Governments