Well, it seems I've got a different approach than the rest of these guys...
In 1994, I bought a 1983 GMC Vandura 2500 - that's a 3/4 ton, 6.2L diesel conversion van. I paid $3,500 for it, and it had 85K miles on it when I bought it. It now has 320,000 miles on it and finally needs a new motor... the motor still runs strong, but has developed a knock (piston skirt?) and a head gasket leak, so I've parked it until I find a good replacement motor.
Up to this point, I've had to do no maintenance to the motor itself, other than your normal filter, fluid, and glow plug changes. I've done stuff to the rest of the van - radiator, brake pads, rotors, master cylinder, starter, etc, but hey, it's 19 years old and has 320,000 miles on it, what do you expect? Whoever said diesels have more maintenance has never owned a good one.
I get 19 mpg, and don't notice much of a difference while towing my 19' Custom Weld... plus, I don't need a camper, I've always got a queen-size bed in the back... I get tired, I pull over and sleep... it is sweet.
You want to talk about economy? How about paying low insurance? I calculated that with registration, insurance, diesel fuel, and parts & service, I'm still only about $0.22 a mile on this vehicle... what are you guys with your new $35,000 vehicles paying?
There have only been a couple of times I wished I had a pickup truck... when I've bought a couple of garden tractors and needed to get them home, and when I thought about buying a driftboat, and started thinking I needed FWD... but I'll cross that bridge when I get to it... and don't get me wrong, I'd take a new DuraMax if someone gave it to me...
Check out this page, it's got lots of good info about diesels and fuel economy:
http://www.62-65-dieselpage.com/mileage.htm -N.