Transmissions are crap. The front cover is bad about leaking which requires engine removal and they have wiring issues. The engines in these trucks are rock solid but the rest of the truck is in Uncle Si's words " That things a peice of Junk". And no crew cab
Each brand has it's own issues. Duramax is the best engine/trans combo but the truck is not as heavy duty as the Ford's. The 7.3 Ford trucks are the best for truck durability but the Auto trans will need some serious attention. They have some front end issues but it is not an expensive repair.
Here is a F350 SRW. Not ideal but cheap and leaves room for repairs.
Do not be scared of pulling with a single rear wheel truck. We do not have mountains down here and especially if you use a goose neck trailer they do great.
If you get up in the 15k range you can find a good Chevy 3500 dually in the early 2000's.