Both of my trucks have typical military paint jobs. CARC applied with runs, flaking off in some places with OD showing underneath plus those rusty patches.
It is obvious that not much if any surface prep was done before painting. All that taken into consideration, that paint stayed on there pretty good for quite a few years before it even started to fall off.
Consider what you have. A $3900 deuce doesn't really warrant a $5000 paint job unless you are doing an offf frame restoration. Then it will be nicer than it ever was from the factory and not correct.
You will have just as much or more fun with it if you just get some green paint on it. Once some of it starts to peel off and show the red underneath, you can scuff that spot up and brush some green paint on it and it will look all pretty again.
This has been pretty well covered, but here's what I would do.
Pressure wash the crap out of it. Scuff up anything you can get to with Scotchbrite pads, and maybe some 80 grit where the paint is thick. Remove whatever rust you can get up the time and enthusiasm for, treat with phosphoric acid or just paint over it with Rustoleum rusty metal primer.
Here's the thing. If you just wash it good and scuff up the parts that are easy, paint over everything but the glass and rubber, paint right over the rust, in a year or two it will look like every other military truck out there. That will get it pretty right now, and you can deal with the rust later. No big deal, it is a 40 year old truck that already has multiple layers of paint here and there. If it looks good from 10 feet you are good to go.
As for paint choice, I decided this weekend that I am never using oil based paint again on my trucks except for primer. That Sherwin Williams house paint looks better than anything else I have tried, Rapco, etc.
I have what I think is the perfect mix for 383 Green. If you want to use Sherwin Williams, I will hook you up with wholesale price to boot. I have used a lot of Home Depot paint, it's not bad. Sherwin Williams is just better. Most professional painters will agree. Oh yeah, you get it mixed by a professional.