I would bone/quarter it as you plan, but get it frozen in plastic bags before starting back. Dry ice would be the best, frozen gel packs second, and plain ice last. I prefer the plastic bags so the meat doesn't end up in water if you use ice.
    You should be able to find a processor, grocery store, or locker palnt that would let you freeze it for a couple of bucks. ($ kind)
Once home you can thaw and process it at you convenience. We process frozen quarters/trim for customers nearly year around.
    Good luck,

Dave & Ruth
D & R Processing