Should be able to swap 12 volt bulbs for 6 volt bulbs in most any of the aftermarket tail lights you will find at the auto parts store.
You will at least need two wiper arms on the truck to get inspected, they probably don't have to actually work, depending how thorough your inspector is. The back glass should be no problem, many many trucks have bodies that cover the back window to start with, so even if you had no glass, or a piece of plywood, you should be fine. The horn may not be a problem either, again depends on the inspector.
I would suggest you ask around at automotive machine shops, and other places where people hang out that work on and with old cars. They will be able to point you in the right direction for a "good" inspection station.
You need the kind where you go in and ask for an "inspection sticker", as opposed to "an inspection"
Grigg
