There is a difference between elk and deer. With a deer, you can field dress it and that's enough to cool the carcass. You can also drag a whole deer by yourself (I've done it many a time.)
With an elk, field dressing is not enough -- especially in warm weather (and I've seen it above 60 degrees at 11,000 feet during the third rifle season in Colorado.) An elk is so big, and so well-insulated that its body heat cannot migrate to the surface and dissipate before the meat spoils. And, of course, you cannot drag a whole elk by yourself (to say nothing of the terrain in which you usually find elk.)
The solution for elk is to bone out the meat on the spot. Under very warm conditions, I make a cut down the backbone, peel off the hide, and bone out the meat on that side, putting the meat in plastic trash bags. Then I roll the carcass over, skin and bone the other side. Put some spruce branches on the ground, put the bagged meat on it, and cover with more spruce branches. It helps to leave a garment with it -- the scent will tend to discourage scavengers.
Take as much as you can reasonably carry -- perhaps the antlers and loins -- on your trip out. Mark the spot as a way-point with your GPS and put flagging tape around the spot, and leave a trail of flags as you hike out.
When you return for the next load, leave everything you don't need -- rifle, binoculars, ammo, etc. -- in camp. It helps if you can get a vehicle somewhere near the carcass. Even better, arrange beforehand for a horse or mule to pack out the carcass.