I have a 2015 338RETS also. I pull it with a 2014 3500 Chevrolet 12 passenger Express van, 138in wheel base. It has a 6.0 gasser with a 6 speed behind it. We leave the forward rear seat in for the grandkids. With all the extra "enclosed" space we can put dogs, bikes or whatever else we want.
This past Sept we went to Yellowstone, Grand Tetons, Devils Tower and the Black Hills. 2600 miles and averaged 9.6 mpg. We drove between 60-65. Had no problems with the grades through Yellowstone. The long 8% ones I would drop down to 50 mph and that was 4100 rpm. No problems with loss of power, overheating, nothing. Pulls great.
Nice having all the extra space that is protected from the weather and thief's. Been pulling with vans for a long time and would not go to a pickup.
REALLY, REALLY like the TT. We did replace the king bed with a queen. Extra space around the bed is well worth it.
