If it were me I would not put the head and cape in the same cooler as the antelope. Is the meat going to be butchered and vacume packed and frozen or just quartered. For just the meat a 125 qt cooler should be fine for the meat, probably a 50 qt would work for the cape and head. I have a 125 qt Coleman and a 150qt Coleman and I have brought back 2 wild boar over 125 lbs quartered twice, about a 12 hour trip, with no problem , hardly any ice melt at all. I also transported the butchered and vacume packed and frozen solid meat from about a 450 lb Bison on a 24 hour drive and the meat was as solid when I got home as when I packed it in the cooler. The trick is to have your cooler very cold, in the case of the hogs my cooler sat in the walk-in for 3 days and the meat was cold when it went into the cooler, a little ice on the bottom and a little ice on the top and I didn't open the lid until I got to the butcher shop. With the Bison, my cooler sat in the walk-in freezer for 3 days until I packed it and once again I didn't open the lid till I got home and put the meat in my freezer. Three of the guys taped the lid all the way around at the closing seam. I did not and there was no difference in condition when we got home. On the one hog trip two of my friends had Yeti coolers and there was no difference in ice melt when we got home. If you put cold meat into a cold cooler and don't open the lid any decent cooler should work for you.