I have an SUV & for me this year if I need to transport over a ways, I am looking into getting one of those Costco Marine Coolers :
150-165 quarts, white (so they reflect the sun and stay cooler longer) and have a 7 day rating. I think they were about $229 last I saw them. One will hold a good sized mule deer quartered, two might even get you an elk (if you butcher it at the camp)
I can either put it inside my SUV, or if needed you can get a hitch carrier and mount it outside :