I just thought I would throw my two cents worth in here.
The east Zion hunt has a low elk population, and the elk are scattered in several different locations. The southwest part, or Kolob area is all private, and yes there have been a total of about 4 bulls killed off there in the last five years that have been from 350 to 435 gross. That area to my knowledge is pretty much off limits, unless you have a friend with property, or you pay one to hunt their land.
The southeast area has a small nomadic herd that roams a large amount of acreage from highway 89 to the Zion Park area. Good luck finding them two days in a row, and on public ground.
The north central area borders the Panguitch lake unit and does have a decent elk population. There is normally two or three bulls per year killed in that area that are over 300, and up to 350 gross. If I had to hunt this unit I would concentrate on the northern border and hope I caught one crossing back and forth to the Panguitch lake unit. It can be a decent hunt, but I would say if you are planning to hunt for big bulls, it's nearly impossible. If you want to hunt "elk" then it's not bad for a Utah general any bull unit. Expect lots of competition,
Good luck,
Travis