My son wants a tree house, but the only trees we have do not have branches low (mostly wild cherry trees and oaks). So I am thinking of trying to build him and elevated playhouse. I am looking for any pics or ideas any of you might have. I was thinking of making it 6' x 8', about 6' to 8' off of the ground. I thought I could use 4 x 4 posts or 4 x 6 posts, but don't know whether to use 4 or 6 posts. SHould I use treated lumber for all of the framing or would regular lumber work for the floor joists and studs for the walls? I was thinking of using t-111 for the siding. Thanks for any input and pics.