I am 69 years old with a left knee replacement and a right hip replacement. The left hip isn't a lot better. I also could lose a few pounds, too. Anyway, I currently own a Disc Trucker that I dearly love. However, I am finding it getting more and more difficult to throw my leg over the bike. Especially if I have a trunk bag on my rack.
You could try a front rack and put your trunk bag on that.