Try oven cleaner just dont leave it on to long. Dont know what kind of paint you have but it worked to get old sponsers off my racecar that are no longer on board.
Archery hunting Elk is very challenging. Been doing it 15 years an only taken 3 animals an one was a cow. Enjoy your trip an the experience. I would keep the california part quiet to
Put a couple a 3 gallons of gas in it an throw it in the back of your pickup an drive around for about a week. Then steam clean it out with the hotsie an see what it looks like. Might be good enough depending on how bad it is.