Stev22,
"Yellowstone and then west or south" and you have an older Yukon at can pull 4500#... here comes the wright police out of me... I don't know where you live but that is not going to work. It does not take much to be well over 4500# in a TT. A lot of them start off at almost that, then the Yukon may not have the muscles to pull over the hill and mountains that are between you and Yellowstone or the other mountains. Wheel base is a important issue in safe pulling of a trailer and the weight distribution and sway control is also important. On my small TT I had a F150 V8 Long-bed and could really feel the load when in GA's small hills or long overpasses. Bought a 3500 and even the grandkids said "Wow papa you can feel the difference" in towing and sway as the big trucks passed me. ALSO remember you are driving/pulling an RV you are not going to be flying down the road at 80mph (maybe 65) so it is going to take longer to get someplace and if you are fighting the vehicle all day it is going to wear you out.
dahkota recommends renting ... this is true, but do it for short distances and for a long weekend. Renting is costly with the fee @ mile, and rental cost. Also they only rent motorhomes not TT's.
