Encumbrance

Players Handbook (page 101)

Whatever you select to carry will have both weight and volume (or bulk). Equipment for adventuring is necessary, but too much is deadly. In order to be able to move with reasonable rapidity and freedom, the number of items carried and apparel worn must suit encumbrance restrictions. (Remember that the volume of something can be as critical as its weight, i.e. 20 pounds of feathers in a sack are cumbersome.) To be useful, items generally must be readily accessible, so this consideration must also be borne in mind. Lastly, as the main purpose of adventuring is to bring back treasure, provision for carrying out a considerable amount of material must also be made.

House Rule

No specific rules for encumbrance will be applied except for common sense. The DM will give guidance, but players should also be realistic about what they might carry.
You won't be carrying 20 torches for a long dungeon excursion. Maybe 2-3 at most!
This is just a general thought about how the weight allowance may be calculated. But I'm going to hold off for just now.
(strength / 10) * height (feet rounded up to nearest half) * 5 = number of pounds the character can carry

Based on the knowledge that the modern day commando final test is a 30 mile run with full pack and weapon, we can take that this is a possible level for a fit and constitutionally strong adventurer. It also assumes limits per day, so that the activity can be continued on following days. Note that walking (normal enc) and running (heavy enc) have the same travel rates, but walking will take longer. Likewise, travel by horse has limitations similar to running, but will be quicker) and assuming one horse. If character can change horses then they can continue for twice the distance per day. But twice is the max.
from Royal Marines selection: "The 30-mile march: This is a march across Dartmoor, which needs to be completed in less than eight hours, carrying 40lbs of equipment and a rifle."