Call Wy. Fish & Game. They're a helpfull bunch and will let you know about winter kill and overall population in given area.
IMHO the best areas are between Laramie and Casper. Shirley Basin just outside Medicine Bow has alot of BLM land and even some private access (or used too,been a few years since last hunt) with usually a good population. I've done DIY hunts in this area many times and always scored and taken 3 B&C lopes. I usually allow at least 10 days of hunting but usually filled my tag by the 2nd or 3rd day. Make sure you have a good spotting scope and to get off the roads and you'll be successful.