These are old school, bullet proof (literally) trucks that were built to be maintained in a field environment. You can, with basic mechanical knowledge and simple hand tools, operate and maintain one of these trucks easily.
The manuals are written on a seventh grade reading level and most of the diagrams show key components and systems in a way anyone can understand them.
I have seen deuces beaten and neglected and still do the job.
They are nothing like the techno marval vehicles of today that take an engineering degree (and deep pockets) to work on.
A lot of civilian parts will cross over and, as mentioned above, there are plenty of sources for parts and assistance to help you. This is one of the best sites anywhere.
My son works at Advance Auto and I had him cross reference some items for me just to see if he could do it. He found almost everything I checked. If he had been older and knew more tricks of the trade he could probably have matched them all.
The archives here have tons of information availible for downloading.
Buy a deuce and have fun.