My days of crawling on the floor to do anything are over. I can get down, but getting up again is a bit of a chore.
If you have a king or queen size bed in your home, use that for your design wall. If you put a flannel backed table cloth on it to hold the blocks, you can just roll it up and put it away when you are done.
I think I'd put some elastic banding on the corners of the table cloth to loop under the mattress to hold it (flannel backed table cloth) in place on the bed.