I have my Crosscheck set up for light touring also. Just a rear rack and frame bag right now but I am looking for a porteur rack so I can carry something like a Carradice for short tours, or a Pelican case on longer rides. 40 lb max load. Once the custom w/Rohloff on order arrives, the cross bike will be dressed with Honjo fenders and narrower tires for shorter duration rides and credit card touring.

To the OP, this is a good example of the range of what "all terrain" means. The other extreme is what are called "expedition bikes" like the Thorn Nomad and other Rohloff equipped internally geared hub machines. Expedition bikes are 5K plus fully outfitted but are capable of amazing feats, climbing the Himalayas and the Andes without skipping a beat. For crossing TN you need nothing like that. An MTB or a bike like seat_boy's is plenty.