Did some practice free mounting, idling and hopping today with the combination of a roofing harness and a rope hanging from the rafters of my garage. It’s a great confidence builder. Roofing harnesses are both common and affordable.
I find the rope alone is fine for practice. It gives you something to hold onto, but requires more balancing than something solid like a wall. The roofing harness on the other hand gives you that little extra bit of confidence to actually let go of the rope.