I don't know jack about Idaho, but perhaps your focus should be on what rather than where.
You can do commercial and industrial electrical, but only as a scab and that can be hard work even when scab work is available. It obviously isn't. If you can repair complex mechanical assemblies, you've opted not to fix your own truck so that obviously doesn't appeal to you. You may be able to troubleshoot electronics, but I rather doubt that you can do it better than zit-faced eager hungry young techs with recent training, young families, strong motivation and willingness to tolerate whatever crap they must for a paycheck. You ain't gonna be a lumberjack or oilfield roughneck at age 60 and beyond.
Your most consistent interest and passion has to do with guns. If you're really serious about a new course, I'd say build on that. You know guns and their use, you can respect people who respect guns, and you have at least rudimentary skills in machining and smithing. The people most likely to be tolerant of your idiosyncrasies are those who appreciate and covet fine firearms and will pay handsomely to have them made for them. There are people with money to spend even in recessions. Hell, you know how nuts sales of AR-15's has been since the election, even in a down economy.
A few men with modest lathes, some tooling and considerable skills who can craft rifles that win BR matches and/or craft pistols that are exquisite in design and function have far more work than they can do even in the present economy and perhaps especially at present. They can live where ever they want and most do live in rural to remote locales. Age doesn't matter, nor does physical frailty that inevitably accompanies advancing age. You say you're good for another
15 to 20 and maybe you are, but I'll note that being 68 is definitely different from being 56. YMMV.