I've cow hunted Unit 84, but only in November. In November, I found the elk near Hoback Junction above the feed grounds and on the south side of the highway on the ridges above the houses & camps that are right along the Hoback River.
In September, if you are not using a guide, I would go up Highway 191 from Hoback Junction to Cliff Creek Road, turn right and go to the end of Cliff Creek Road. There is a trail head at the end, hunt anywhere to the west from there. There are also a few pulloffs along Cliff Creek Road before the trail head. Most of these pulloffs along Cliff Creek Road have old roads/trails that go west, try hunting west up the old road/trails.
Other places to try would be up Dell Creek Road, just stay out of the wilderness areas. Also the northwest side of Jack's Creek Road, above the elk feed grounds.