A fasteddy version of a mobility scooter sounds like a good plan. I mean for real, not doing wheelies with fantasy gas motors and all that. Even just a used mobility scooter like real geezers use. You're going to need to get around safely and be able to tinker out in the garage. Any chance of setting up a bed or cot in the garage/shop so you don't need to go upstairs? I guess I'm thinking along the lines of making lemons into lemonade... some strategy to deal with your situation so that between now and December isn't just waiting. We're too old to wait. There isn't enough time left to be waiting. My opinion anyway. I keep thinking of Burt Munro in his home/workshop happily working on his Indian. I've seen you lose track of time making sparks with the welder, off in private visions of metal flowing into itself and morphing into a motorbike, trike, cyclecar, velocipede. Then flipping the helmet up to give the work a good stare and accepting a cold beer from an appreciative friend. Make some sparks, Steve.
You got dealt a tough hand, for sure. I think you need some new and better cards, Bud. (Cheating is not only accepted, but encouraged.)
SB