Two of my three escapees were found FIVE feet off the floor on bookshelves far removed from their tubs. I think they like to climb IF things that are sturdy are available to them.
If I were independently wealthy, I'd love to build a HUGE environment, like those found in zoos, and include things like climbing structures big enough to support an adult cornsnake, and then see what a cornsnake did with all that space.
Truth be told, if I was going to go this route, I think I'd go REALLY HUGE and build an environment that would be potentially adequate for TWO cornsnakes and then monitor closely to see if they could safely cohab if they had several hundred square feet of floor, plus trees, plus several large water bowls for bathing, drinking & swimming, plus multiple warm spots, etc, etc. But this is just a fantasy, and unless I win the lottery, I am not going to cohab snakes. I just think it's a great fantasy, building fake rocks, maybe getting a live tree that could live in that environment with appropriate lighting, etc, like building a gargantuous terrarium.