If you come up dry, check out HARP at Floyd Bennet field. Might be able to work a deal with one of their volunteers. Aircraft work is likely not the same, but may give you enough hands on to adapt to what is required on your coach.
There are some active aircraft renovation groups in the Bay area and you might get some instruction from one of the Fairfield Dealer techs or maybe from Vinney's over in Winton.
It would seem that you might build an aluminum battery storage box, a tool box, or some other project for practice. You might pick up the Prepare to Win book by Carroll Smith. It's about race cars, but his information is transferable. Talks about eliminating stress risers and how to fabricate brackets. Not bad information to have if you are the hands on type.
Hope you figure out the plan. Good Luck. Pat