Zac, once it dries, it is hard. If you have a little flexing in your frame, it will likely make it more stiff. If you have a stiff frame, you should be able to lay almost anything on top of it.
This is the same material (coarse woven cloth with powedered plaster) that once wetted, will set to the strength of a body cast (over your arm or leg) only they use several layers. You will need a sharp point or drill to make holes for trees and a sharp construction knife to cut larger holes.
