Hey Growmie,
I've personally used a cardboard box to dry in so that that part will be fine, but what you'll need to watch for are the humidity and temp and make sure they are staying in the correct range, which could be the tricky part since your actually drying room is outside, you'll have to take in consideration the temp and humidity outside will affect the inside of your sheltered, if you can stay on top of that I don't see an issue with this at all. Feel free to shoot me a holler if you ever need any help, I'd be honored to assist you. Hopefully, this was helpful, and remember ... "Happy Growing" and "Free your mind one puff at a time".