I really appreciate this question and comments, I am planning the same trip in 2015. But from what I see it, the question is not which vehicle to TOW.
But rather which vehicle weights less and will do the job required for what I want to do.
I do not plan on going 4 wheeling or climbing the mountain trail with my vehicle, however if there is a small stream or water flowing over the road can I safetly drive thru it and get to where I am going. I wont be driving old haul road thru the wilderness. 99.9% of the roads will be normal daily use roads used by everyone in the state.
So which vehicle will do the job and weights less when towed. A 2002 with many miles, or a 2014 $40,000 new vehicle?