Thanks guys, I'll have to take a close look at Gaia. I had not even noticed the name in my research up to here. It's a good thing I asked.

Power for a gps is my next challenge. I find that there are 5400 batteries available for the Galaxy (though they require a new back), and I suspect that having two of them would get me through at least four days, and I can still use the original battery for another day (the batteries weigh very little, charge in a two-battery external charger fairly quickly, and are reputed to hold their charges for as much as ten days unused. Unfortunately, they ain't cheap. The price I saw was about a hundred bucks each, plus another forty or so for the two-battery charger.

But so far, that's the best I've been able to figure out on logistics for long trips. If anyone has better ideas, let me know, pls. thanks.

Without the GPS app, I have been able to go ten or twelve days with just two regular batteries by the simple expedient of turning it on only one hour each day (plus when I want to shoot pix). It may be that I can figure out how to use the GPS only for short periods as well, but suspect that may obviate some of the purposes for which it's attractive to me.

All reflections welcome. Thanks, best, jcp