Worth it to buy whole donor vehicle vs just engine?

[TrybalRage]

Hey all. Considering an LS swap for my 1985 longbed. I'm hoping to turn it into a reliable daily and a vehicle that can tow my 17' boat without issue to locations that could be several hours away.

Currently I have a 2016 Ram 1500 that gets those duties, but my lease is up in July of 2020, and I'd rather say goodbye to that payment... so as I see it I have roughly a year and a half to get my C10 redone.

In the early stages of planning, I'm wondering if it is worth it to try to pick up a whole donor vehicle rather than just an engine/trans on a pallet. My thinking is, I'll have all accessories, wiring, PCM, etc, along with possible other parts that could be used in the swap. (radiator? fuel tank? others??)

I guess I'm wondering how much of that will just get junked anyway to be replaced with new/modified stuff in the process.

Is there money to be saved by starting with a wrecked donor truck/suv? Does this make the job "easier"?

EDIT: For clarification, I'm eyeballing a 2005 Suburban with ~200K miles on it.