Its great to be able to get that great big bolt off the floor, isn't it? I had the same problem once till I finally came up with a similar idea as your son. I used a very large diameter dowel road, added an eye bolt to both ends and to the rafters above as I'm in the basement with open rafters. Took a couple of clasps like you use to keep your keys together (or I do) and slipped it thru the eye bolt on the dowel rod. This way I can take it off and on easily. Has worked for me and my floor is cleared. Isn't it great when we can come up with ideas that cost us little to nothing but what we have around the house to make it work?
I get some great ideas from those on this site. Thank you.
Suz in Iowa