I'm driving a '96 F-350 Crew Cab 4x4 PSD singel axle now that I love, so I'd probably vote for that. The newer ones I've ridden in are quiter, and I've seen more of them turned into hotrods, but mine has been rockin along for 10 years now from Alaska to Texas in nearly every kind of weather, rain, snow, mud, mountains, desert, and swamps. Its never left me stranded and is only 150k miles young. Its taken a few dings along the way but still fires up every time I turn the key and has never balked at pulling anything I've tied it to including an 80' house trailer and my father-in-law's tractor that happened to be tied to a 14' diameter stump that had just been pushed up by a dozer. I'd say you need a '96....

 

A picture of a Ford pulling a trailer house down the road would make a great commercial. I don't think you will go wrong with the 7.3 PSD in any year.

 

My 3 cents would be:

Make it a true superduty, the newest 02/03 7.3 Turbo, best mod potential, make it either a 5 speed torque**** auto or a ZF manual.

Also, a KR or Lariat if you can is sweet for options if you are lucky to enough to find in goodshape.

Have it checked by a meticulous mechanic or yourself, check brakes, tie rods, ball joints, all fluids, frame, tires and shocks and use to negotiate price.

 

In my limited opinion, I would have to suggest the IDI engines.

The InDirect Injection is probably the best suited for grease conversions, there-after (with the price of fuel) making it a money maker... as long as you can get grease for free.

I am 5'6" and have an '86 F350 Quad/Diesel/longbed/dually (that I am getting ready to convert) The best thing about it is even after 20 years, it is ready to go to work!
and while it is somewhat larger than I may need, it isn't overly large.
With a newborn son, it is going to get somewhat smaller as the years go by!!!

 

I prefer the 2000-2001 models. They have all the updated stuff and they also have forged connecting rods. I have a 2000 model.