I live in that neck of the woods. I don't hunt Antelope, but I have used many of the Walk-in Areas(WIA) for deer hunting and have seen fair numbers of both deer and antelope on them. It seems to me that the majority of the hunters don't stray too far from the roads. I'll paste a link to the Wyo. G&F site for the WIA. They have it in book form available at the license agents. They might mail you a copy if requested. Look around the G&F site as I believe drawing odds are hidden there someplace. If my place were a little bigger, I would let you come shootall the antelope you can buy tags foroff of my porch! They are a nuisance around here and they are hard on my trees.
http://gf.state.wy.us/wildlife/access/plpw/huntingwalk/hunting.asp