Make sure you build it tall enough if you want to hang whole field dressed deer. Even with the rear leg shanks cut off they are surprising tall with their heads and racks still on.
if you don’t need a permanent location, the Koolabuck is pretty solid and a complete package. You can get it up and running in about 15 minutes and holds temps below 40 even in 80+ degrees and direct sunlight (like the buck I had hanging last week).
And at the end of the season it packs down pretty small where my wife barely notices it. I have the Jr. model.
I built one in my shop that is 4x8x8. I framed the walls with 2x4's and used fiberglass insulation in between the studs and a vapor barrier on the inside wall. On both sides of the walls, I used 2" poly styrene panels and covered with 5/16" osb. I used a 12k btu with a Ranco temp controller.
I’ve been hanging moose in a setup like this for a number of years.
12x8’ dimensional (bldg materials) space 4” of hardboard foam (blue board or r tech) in the floor, walls and ceiling. Put two rails on the ceiling for rolling meat hooks.
Put the Chillbot and cooler anywhere in the walls and use a mobile blower fan to put a skin on your meat.
Lay a $5 tarp from Walmart on the floor before you hang meat. Either pull it outside in a rainstorm to wash it off or throw it away when you are done.
Use small wire hooks w/o rollers for backstraps and T/Ls
You can get foam pretty cheep by buying old roofing tiles and giving them a good whack with a framing hammer to get rid of the concrete.
Find a free exterior door on fb marketplace and you are about set except for 2xs and plywood.