I think you guys are missing his point and not answering his real question. I don't know the O/P's actual age, but I do know it can be a real problem. When I was 78, I would have tackled removing the front seat and installing a new harness in my '51 without a second thought. Now, at 81, I wouldn't even consider it (and my doctor would freak out).
Although it may come at different ages, we all come to the point where we just can't (and shouldn't) try things that we are no longer suited to do.
All I can offer to the O/P is that it probably depends if there is someone local who does this sort of thing. Luckily, there are two guys withing 25 miles of my home, so there is at east a semblance of competition. Last summer I had the leaks (timing cover, valve covers, and oil pan) on my recently rebuilt engine in my Corvette fixed, the rear brakes repaired, and a couple of other things. I also had whole bottom of the car cleaned of the residue of these leaks. It took the guy two weeks and cost $2200, including parts.
Sorry, just missed the previous post by this much.