I would go with the 1998 dodge if you can find one. It would have the MECHANICALLY injected 5.9 Cummins. I would try and find one with the manual transmission, but even the automatic version in the early years was not computer controlled if I remember correctly.
The mechanically injected Cummins is as dead reliable as you can get. It doesn't need any electricity to run, only to start...and stop

So as long as the truck is running, you could theoretically rip the battery off, the alternator could blow up, and all the wiring could burn, but the truck would still function.
The 94-98 versions also have the inline piston injection pump. I have seen even the 160hp version of these motors make over 600hp with just a few modifications. These motors have potential!
The front axle it the weakest point. I would suggest ditching the CAD and installing 35 spline inner axle shafts and side gears ( or locker ). The outer axles are a 33 spline uni-bearing setup. You don't get hubs, but its a strong setup. You can use some junkyard ford TTB D50 stuff for a homebrew hub conversion if that is what you really want. The rear axle in the diesel should be a full floater D80 hybrid with 35 spline shafts. Personally, I would look for a later model 01.5-02 (?) rear axle with discs to swap in, it should generally be a bolt in. Big brakes are nice.
Well.....that is my vote.