I’ve wrestled with the same problem. I manage and play in a chamber orchestra. I’m always loading tympani, bass and other instruments into a minivan. I’m also in my mid 60’s, so I appreciate your concern. Big amplifiers are about the worst thing to load. The idea of a lift is not unreasonable. My brother is in the plumbing business and he has a rig to lift the heavy drain cleaning equipment in and out of his plumbing van. Since my musical activies is not a full-time occupation, I just live with it and try to get helpers to load and unload the instruments.