I just found this site you suggest to me.
White River is tough to get onto.
I have tried and usually end up subleasing from a friend who has a fossil lease on a ranch in Wyoming. One story I heard from someone who lives in Chadron is that a rancher let some folks onto his land and they left a gate open. His prize bull got out and impregnated a handful of his neighbors' cows. The bull owner loses lots of money that he would charge to use his bull's services, and the heifer owner has calves he didn't plan or want. To city folks this may seem like a laugh, but we're talking about peoples' livelihoods here.