I've scouted a bit in that unit - I hunt just across the road from there to the north. Anyway, you should do fine, 70-75 should be pretty easy in most years.
Pretty sure they had a good wet spring so horn growth should be good this year. From what I see in that area, the bucks tend to have really good mass but not many tall ones, not saying you wouldn't get lucky and find one that's 16"+ but a lot of bucks are in the 14" range but will have a ton of mass which makes them tough to judge IMHO.
They (SNS) has access to some really good ground to hunt. Do you which end of the unit you will be on?? I'm most familiar with the north end of it.
As far as terrain, its pretty typical antelope country, some pretty open and some broken stuff that lets you stalk in pretty close if needed. Since you will be there for the opener the antelope should still be more settled down versus later on. I will also be in my unit on the 1st for the opener - just keep your fingers crossed it doesn't rain or snow - that can make it tough to get around.
Good luck to you on your hunt - be sure to post some pictures!!
Here is a pretty typical buck for that area, got this one last year opening day, I think he scores right about 75" or so gross, not huge but a pretty buck.