This is why street trials make a lot of sense to me. Anything becomes a session-able obstacle, and you don't have to travel anywhere. You can practice in your driveway/parking lot/basement. And all of those skills transfer to the trails when you get the chance. Also, almost all trials moves are done at low speed or stationary, so high speed accidents aren't an issue.
I built a Giant STP for this purpose, originally a two-speed that used a barrel adjuster to shift, and many permutations later I converted it to a 6-speed so that it was easier to ride to other spots. And bought those Jeff Lenosky and Ryan Leech DVDs, back when DVDs were a thing.