Nice post ED and it brings up several things that could be helpful to you.
I am 58 and pretty busted up as well. I have artificial joints and fused vertebrate all over this old carcass but once a Marine... anyway, recognizing that the more I give into the slowing influence of age the quicker it will progress I have increased my play time at the range to help offset this process, with the thought in mind that if it was not fun I would probably not do it.. (include list of retired exercise equipment cluttering up the garage here..)
A couple of months ago I looked into some shooting competitions that my local range hosts.
are a couple of links to help you find out what might be available in your area.
Anyway i'm pretty new to this but I have participated in two matches and I'm having a blast. Yes I suck compared to most of these guys and gals.. but the friendly and helpful attitude of these people are a benefit I had not counted on. I think I'm hooked and I'm definitely doing something I enjoy.
Hope that helps Ed!