Yep he is just about 4 1/2, next month. I am finding him before I go to bed sleeping in other places. When I wake him up to go pee before I go to bed, I put him back in his room, and he wakes up there. So I think sleep walking is out.
He has always played before he falls asleep. It's his way of winding down. He is not generally disruptive, only occasionally.
I did tell him tonight that if I keep finding him other places that the fort will have to come down. Hopefully that will take care of the problem.
Like PP mentioned, I really don't want to punish for something like this. He was so proud of it when we got home. He was excited to show it to us. So I would like to keep it until he gets bored with it.