If gas is an issue for anyone, I can carry extra fuel. I'm considering taking hte KLR instead of the XT to test out some new luggage. If I take the KLR, I can easily take extra fuel, and let you swipe it out of my 5.5 gal tank (I carry a hose for just such occasions).
I recommend you take the lightest bike you've got... so if it's just fuel that's the concern... I'll pack extra for the group. I can get my KLR most anywhere, and would rather those with the lighter bikes, are one them, so they're having a good time and aren't concerned with the weight of a bigger bike in the tight places.
Ride your own ride & enjoy your ride.