I was actually looking at older stuff, and MDTs. I just can't justify spending 20K+ on something that realistically is going to be used a max of a couple dozen times a year right now, and around here, even a lot of the older diesel pickups seemed to be owned by people who think they have a chunk of gold parked in their driveway because "diesels last FOREVER!!!"
Between the camper weight, the extra stuff I'll be adding under the frame such as larger water and waste tanks, generator, compressor, tools, etc and trailer tongue weight, I'll be overloaded on even a newer dually. I know the manufacturer ratings are a bit on the conservative side as a CYA measure and having to account for dumb people doing stupid things, but I'd be more comfortable being within sticker loads just in case there's ever an incident and the other side ends up with a shark lawyer.
As far as power goes, I don't think I need big HP numbers nor do I really even want to get into the drivetrain modifying side. If I end up with something that will comfortably cruise at 55-60 with my load, I'm a happy camper (pun partially intended, lol). I've had 10K+ behind my current Ram, and power wasn't an issue at all..suspension very much was. If it wasn't for the need to be carrying 4K-5K pounds, I'd probably just throw a D60/D70 combo under my current 1500, bag it, and pay damn close attention to the frame for signs of fatigue failure and then put in a 66RFE when my trans gives up the ghost. But that stupid heavy slide in camper changes the whole thing.
I started looking at the Mitsubishi Fuso and Isuzu NPR style trucks (and I still can't figure out what the difference is between all the different N** models), flatbed versions of the International 4000 series trucks, F600/F700/F800 (although that's creeping up on HDT truck territory too, I think), etc. I found a semi local IH Fleetstar (I'm an old IH fan, already having a '59 and '62) that was dirt cheap, but insurance was going to be a nightmare apparently due to it being a tandem axle, and I'm not equipped to do a single axle conversion unless it would be as easy as unbolting/torching off the rear most axle and rolling it out.