Scroll down a bit to the "i'd love to see your mountain bike conversions" thread; it just inspired me to tour-out my old miyata.
A friend of mine (who is a gigantic person) rolled on a fargo for a minute, and hated the geo. I mention that he is huge b/c the fact that he is a big guy on the biggest frame size might mean that your impressions of the geo might be markedly different. (Of course, the same may hold true even if y'all are similar sizes. ) The thing is, my buddy was verrrry enthused about the fargo build, and he thought he'd like it b/c the geo is similar to a jones bike, and he loves the jones bike's ride. So, that he was so disappointed came as a huge surprise to me.
My take: the fork on the fargo looks weird, and i imagine that has to translate into some weird handling. But i digress.
My recipe: find a hardtail that you like. Personally, i'd go 26" over 29", especially if you want to tour, but whatevr you prefer. The Surly KM would be a great choice,as would pretty much any older-style mtb. (I like steel, but do whatcha want.) Build it with v-brakes, a typical wide-ratio mtb-style drivetrain, and some bars that allow for multiple hand positions(so many to choose from; pick your preference.) I'd get 2 wheelsets, so you can run knobbies on one for singletrack, and slicks on the other for touring/gen bike purposes. Also, if the smallest cog remains the same, you could run different cassettes on each wheel to maximize ratios for the style of riding you're doing. Removing fenders for trails is highly recommended, but the racks can stay if you don't mind the weight. (The bags, on the other hand, might jiggle excessivley.)
Enjoy your one bike with the dual personality. If you can't afford two wheelsets or it offends your minimalist sensibilities, you can just swap tires each time.
hth
-rob