The ewe hunt I believe is valid for the Washakie Wilderness and the Greybull River drainage.
I think the definition of the "Greybull River drainage" is what one would have to look into for a self guided hunt. There is a lot of non-wilderness country that I believe would fall into the "Greybull River drainage", including the south face of Carter Mountain, Francs Fork, Timber Creek, and Wood River all flow into the Greybull River. A lot of sheep in that country. I think those areas should fall into the definition of the "Greybull River Drainage". That is the country I killed the ram in my avatar in.
I am not the expert on what that definition includes, and someone would have to do their homework.