My first thoughts keyed in on that word "cave" and even 14x20 can get cramped! I'd opt for upstairs sunlight, HOWEVER with the gutter fixes and using plastic storage OFF the floor, and plenty of light (heat is good too!) perhaps the cave is better. Forget those Damp-Rid containers (which do work in very small spaces) and invest in a good brand DE-humidifier, it takes care of the whole basement and keeps that basement odor away. Good luck.