Re: Public access Wyoming units 63 & 21
I see you are new to antelope hunting. The advise so far has been good as far as what to expect. I have hunted there every year for 25 yr plus and as the others said the weather can be extreme & change in a days time from short sleve shirts to below zero wind chill. The bentonite in some area soils will get impassable with a very short rain shower or very little snow. It will get so slick that you cannot stay on a level road much less one with any slope. That said, moisture out there is not a common thing and you just have to work around it.
We have always cared for own meat and approached it several ways. We used to take a small chest freezer on a trailer. While in town just plug into the motel. On the way home we carried a small generator to run it. For the last several years we have just brought huge coolers and stored/transported it in them. They are simpler & if you are not out too long work OK. Boned out antelope do not take up much space and you will be surprised how many you can put in a 100 qt cooler. One important thing to know is that the WY. law requires that you leave evidence of sex ATTACHED to the meat & they are VERY strict on this. It is a good idea to just chunk up the meat in as large as possible pieces & leave the evidence of sex attached. I normally bone an entire rear quarter into one piece & leave it attached. Work it up after you get home & transport it so the Game & Fish agent can inspect it easily to verify this. If you have either sex tags it is not quite as urgent, but, with doe/fawn tags beware.
Another thing you will find is that there are few trees to hang & skin your game. The ranchers frown on hanging them from the windmills around the water tanks for obvious reasons. We take a rack that fits into the truck receiver hitch. It works great & you can work up the game anywhere, drop it into the cooler & be on your way. Take game bags and keep each animal seperate with the tag & hunter info for that kill.
Last advice: I am not familiar with the area you mentioned as far as specific hunting expectations. Most first time hunters shoot too quick because they do not really know what to expect and are afraid it may be their only chance. It is wise to take your time if you have enough days for your hunt. Most first timers have several opportunities to have taken a better buck, but, have filled out on tags. Buy some doe tags and get used to long shots in the mean time.
In our area a 14 inch buck is the equal of an good/avg 8 pt whitetail back home. Nice, but not uncommon. Know your rifle and how far you can realisticly expect to hit a paper plate: that is your effective range. Antelope are not a hard animal to put down so the only reason to shoot a very powerful rifle is to increase your range. A 243 will flatten an antelope at 400 yards easily if you hit that paper plate size area in his chest.
I hunt with 2 guns for very different approachs to the sport. I love to shoot at long range and use a 270 Weatherby Mag because it shoots so flat & does fairly well in the wind. IT WILL BE WINDY! I also hunt with a Freedom Arms 454 revolver because I like to test my ability to out do an antelope in it's own home court. My max range for a sure kill with the rifle is about 500 yards, handgun about 125 yards. Avg kill for our hunters over the years with rifle would be about 250 yards. Longest rifle 665 yards, handgun 180 yards.
Good luck & check out areas with a lot of walk in hunting land. They are usually over populated with antelope & the ranchers want them killed so they sign up with G&F to get more hunters.
Hope to see your picture on the cover of OUTDOOR LIFE with a real big un!