trash bags will restrict air flow and will probably not be the best idea if heat is an option.
When I mentioned trash bags, I only use them if I am able to get the meat in an ice chest or refer within an hour. If your packing meat out of public lands and it may take hours in heat, I would definitely skip the trash bags and go straight to game bags with a light dusting of black pepper.
2-3 game bags and a small bottle of black pepper is really cheap insurance and shouldn't weigh more than a pound or so; and I would bring a heavy duty trash bag so you can split it down the side and stake it down with some sticks for a clean surface to lay the meat out on as you quarter and de-bone it.
Just my opinion but I find it easier to gut, skin, quarter & de-bone all the meat at the kill site and carry out only meat.... if throwing the whole carcass in the back of a truck and hauling it to the barn is not an option.