Youngins love to climb, so branches for them are always cool. Adults don't climb much at all. But according to a couple sources I've read: balls in the wild are often found sleeping in small shrubs in the savannah waiting for food. I'd like to see a ball python live in an arboreal enclosure though, just to see it's behavoir.

Their bulky muscles make them good at griping things. I once watched Monty climb 4 feet up a scarf dangling. It was cool.