Well, the good news is that a Jeep isn't a tough vehicle to paint. Once you get the old paint off, and the rusted and missing places filled in, it is mostly painting flat surfaces. I would suggest a commercial truck painter over the neighborhood collision fixer.
In the KWAS catalog, about page 45, there is a paint chip for USN Gray which is shown as a color for that model and year. Then, you have to decide if that color goes up under the hood, is it the interior color, what about the under side ...
Choices, choices, choices.
The g503 and steel soldirers forums may have more information on just what color goes where.
Post us a picture - we'd like to see the starting place!