Good decision on changing bikes for the ride. I also have a GS but rode the TAT two summers ago on a XR650L. You will find that with a full tank of gas and your gear that there will be times when you wish you had an even lighter bike. From experence I think that you will benefit from lowering your gearing from stock. Navada as well as CO. Has some very steep and rutted, rocky sections. I did use the 606s,which did well, got new tiers in Moab.