Don't go with a road triple. I used a Sugino XD600 (46,36,26) and was happy with it. The price is right too. On the transamerica the ratios were fine in the Rockies, but in the Appalachians you might prefer a 24 or 22 inner ring.
Other MTB cranks are fine too, but the road cranks usually only take a a 39 tooth or larger inner ring. That is way too big if you will be in the mountains.
XT stuff is nice I would stick with it especially if you already have it.