" I am wondering if I would be better off parting the truck out. "
Only you can answer that. It is relative to where you are regionally as to prices and whether there are people in your area that want parts. Also, if you paid too much, you can never come out either way. But generally speaking, you can part out a truck for 3 to 5 thousand. The easy stuff goes first and you have a lot of hulls sitting around for a good while. The fact that the engines last a really long time means that there aren't too many folks looking for an engine. Also there are lots of other applications for the Cummins and they have been building them long enough now that they simply are not scarce. About 10 years ago, I sold a stock 40k mile engine for 4500 dollars. I doubt one would bring half that now.
If it is fwd, then you have more value with the front axle as opposed to twd. Is the interior good enough to be desirable or is it doged out?
Probably you need to drive it, or sell it whole.
James