You have to go equipped for the possibility of everyone tagging out, a hot day, a long pack out, etc. Murphy's Law prevails. I know it's hard to hold back sometimes, but you do have to think before you pull the trigger and consider the aftermath of your shot. If you shoot an animal early, you do have daylight, but also the heat of the day to contend with. Those late in the day shots (especially in Griz country) create some new problems; darkness, tracking, predators, etc. I packed out five critters this year; two deer were on a high mt. backpack hunt. We boned out the deer, put them in game bags, then in a heavy duty plastic bag, and cooled them down in a creek. When the day cooled, it came out of the plastic, and we hung them in a shaded tree. The first deer was good for three days, the 2nd was packed out the day after it was shot. For a back country elk hunt, unless you have a football team along with you, (or horses), all hunting has to stop once the first animal is down until it is properly dealt with. I look back on some of my early hunts, and now consider it was fortunate that we weren't successful.
For the antelope hunts, it was more civilized. A couple Yeti coolers full of ice, a generator and small freezer. We had the option to refreeze ice jugs if necessary, or use the cooler for the initial cool down. As it turned out, the quarters of the first loper just cooled down overnight before deboning and in the coolers the next AM. The generator was handy to run the big lights for the camp butchering in the dark. (I would NRVER) do this in bear country. The two does were both shot early, we put the quarters in the freezer until cooled, but not frozen, and then into the coolers. After that, we just topped off the ice once in town. 100% meat salvage. Plan for it, and all will be good.