Diesel Diesel Diesel.
Now, with that out of my system, talk to a dealership and find one that
will let you test drive one over the weekend to see what kind of
mileage you get. Sure, you can't try it with your 5th wheel on it, but
it'll give you some kind of idea. Also try one, in similar
circumstances, with the Diesel.
After going from a 98 1500 360 extended, short box, 4x2 to a '02 2500
Cummins regular output (not the HO) 4x4 extended, long box and getting
better mileage than the 98 I'm sold on Diesel. I don't pull much or
often but when I do it's infinitely better than the old gas one.
If you get the Diesel I'd recommend gauging it out (meaning installing
a fuel pressure gauge (to see what pressure your injector pump is being
fed; if the lift pump goes bad it can eat your injector pump (based on
my experience with my '02)), boost gauge, exhast gas temp (pyrometer)
gauge, transmission temp, oil temp, and differential temp gauge) so you
know what it's doing.
I hear a lot of suggestions of running anything to help lubricate our
"Americanized" "dry" fuel (low sulfur fuel; i.e. low lubricity); so use
some Marvel Mystery Oil or some of the (I'll get this wrong) Power
Service or whatever Diesel Kleen/anti-gel, whatever additive, to keep
the fuel system in top shape. The stuff is dirt cheap, and the extra
power and mileage you'll get out of that Diesel engine should more than
make up for the little extra effort you'll put into it.
That's what I think.