I often see guys on TV carrying full backpacks while hunting, and I had a hunting partner once that did. I've always wonder what they have in those packs, and why would they need to carry it around all day while hunting. Now I know. Their packs are full of all the latest gadgets that, if they are on TV, their sponsors are selling, or if they are just regular hunters, their packs are full of the latest gadgets that people on the internet tell them they need.
I have been DIY hunting for deer, elk, and anything else I could get a tag for in Colorado or Montana almost every year since the mid '60s. Except for one whitetail doe, I have field dressed every animal in the field, where they fell. I have been very fortunate that those animals include 3 dozen elk, at least 3 dozen each of mule or whitetail deer and pronghorn antelope, 3 bighorn rams, 2 Shiras bull moose, and a mountain goat. On most of those hunts, including one of the moose, all of the sheep, and the goat were taken on solo hunts.
I have never tried to hang an animal in the field to dress it. One whitetail doe I brought home whole and hung it up to dress it. When I open up her chest cavity, the blood poured out splattering all over everything and leaving a muddy pool on the ground under her. And then I had to put the guts in a double trash bag and haul it off to the dumpster. Never again! If I want to have an animal mounted, I'll usually cape it in the field, otherwise I leave the hide on the animal until I get it home. That helps to keep the meat clean, and it reduces the amount of dried meat that I have to trim off when I process the animal.
Hardcastonly recommended carrying some parachute cord with you when hunting. I have done that for years, and have found it to be useful for many things, but most importantly to tie off a leg to help keep an animal open while I am field dressing it. For larger animals like elk, I'll often quarter the animal and hang the quarters in a tree to help them cool.
All animals should be field dressed and opened to cool as soon as possible. Especially early in the season, larger animals like elk, if left undressed in the field overnight can sour by the next day.