I have a 1988 econoline with a 302 5L V8. I’m trying to completely scrap old wiring from the back that used to connect to shore power, a second battery and the alternator. Wondering if there’s any manuals or guides to help me figure out where everything leads, what not to remove etc. currently have misc wires under the hood and all of them are the same color.

 

Sometimes some things are better if left alone.
Since there is no set way things get hooked up, difficult if not impossible to tell what to remove and what to leave alone.
If you want to cut down on the number of wires, the only reliable way is to trace the wires and see where they go.