Last year was super dry during the summer in that unit. Some of the water sources totally dried up by the end of the summer and antelope tended to migrate long distances from where they were earlier in the summer. Where there are good water sources there generally are more antelope.
Cover lots of country. Some areas don't have many antelope. If it snows much the antelope can dramatically change locations. I would bring lots of water, shovel, and chains. If it gets wet that country can get pretty mucky.