Ladders and Rails should be able to float freely.

Rails floating freely would let you create Donkey Kong / Indiana Jose esque scary roller coasters or let you put them on top of wooden fences for an old fashion wooden roller coaster Aesthetic.

Letting ladders hang like rope ladders would be very cute.

Edit: u/yah-thnpat-thn said "I think instead of floating freely, rails should function similar to scaffolding. They can go out a few blocks unsupported, but break if you go beyond that."

I think thus is a much better idea!