if you are going to be sleeping in there, and hauling ski with gasoline etc.. you may really want to consider a rooftop vent and or a fan. I work in fibersplicing trailers and can tell you, it gets musty and hot inside. and if it rains you may be dry, but you will probably wish you had a window or vent to crack open. If you havent already closed up the walls, it would be cheap to throw a little insulation in the walls to cut down on noise and so on while in it and using it. otherwise it will condensate like the outside of a beer can and and drip on you..my 002. good luck