What are the dimensions?
In my 18x18x18 Exo-Terra I have a vaguely "L" shaped piece of grapevine that goes from one diagonal corner to the other (front/right/bottom to rear/left/top). In a 48" long fishtank enclosure I bought a shower rod to be a climbing branch that goes all the way across.
Since a tank/tub is low friction you either need something that can stand up (so it has to have one side with a base) or it has to go diagonal so the sides of the tank prop it up.
For baby snakes you could whip up a nice little play-gym out of plastic tinker toys. I've seen people do PVC climbing gyms for bigger snakes, this is just the miniature version of that.