What is the gross weight listed? That is the best one to work off of. Pin weight will max at about 20-22% of the gross.
You prob have about 15500 gross and thats about 31-3200 pin weight. You need a truck that will handle setting 3200lbs on the rear axle.
Diesel or gas, I lean toward diesel. Any of the big 3 are good trucks, you just need to make sure you can put that 3200 lbs on it without going over the axle, or worse, the tire ratings. For sure, if you have to settle for a single-rear-wheel truck, it better be a 350/3500 rating.
2016 Tiffin 40 QBH
2015 38RSSA, traded
2005 TK3 #1869, 10 yrs of memories,
2017 F450 KR--one more Ford is it
2009 F450 4x4-died; 2010 F450-retired