Just look at a map and find the ridges that are surrounded by private lands on either side. Then find a way to hike out onto those ridges through public lands. Uintah County can print you out a pretty good map. You can even scout by glassing from the roads onto the ridges, but you will have to hike you guts out to get to them without trespassing. It can be pretty frustrating when you can see elk 800 yards from the road on public land, but it is a rough 5 mile each way hike to get to them and then to pack it back out.
I am no expert on Diamond Mtn., but did some looking around to see exactly what the conditions were, and I decided to apply elsewhere. Not nearly as many animals in the areas that are larger blocks of public land, and access is possible but really inconvenient in the other areas. Bulls aren't the biggest out there either, some decent ones, but lots of mediocre bulls. Good luck hope you guys have a fun hunt.