...the vehicle is going to be used in Alaska (bought in GA and driven to Seattle where it'll be shipped further north). Roads are 99% dirt washboard, off-road is marshy till you hit the permafrost. Winter is mild, but 4x4 is needed occasionally to get going (some snow, but nothing TO aweful deep). The area is FLAT, flat... flat so crawling isn't the primary goal.
Where are you moving? I can't picture what place really matches that geography (and I've been end to end of this state)...for instance, permafrost puts you nowhere you're likely to have a mild winter.
We drove a 96 T up from MA a few years ago. It fit as much as we could pack, and we shipped the rest. Boxes on the two trucks are roughly the same size. The V6 is plenty of power if you don't plan to tow and gets moderately better mileage than the V8. Can't say I've driven a Tundra, but I suspect you'd have plenty of head/leg room in either. The Xcab in the Tundra does look a bit roomier, and the 3rd door is a nice feature.
If you want something to 4x once you get here, I'd go T100. If you think you're going to get into towing toys around anytime soon, then probably a Tundra, although the 3.4 will tow a couple atvs or sleds without trouble.
Also, 15k probably would net you a T100 in better shape than a Tundra for the same money. Figure a T worth that much probably has (should have) recently maintained steering, brakes, tires and so forth whereas with a 15k Tundra, you're paying more for it's youth and moderate to no maintenance thus far in its life.
