There definitely are good numbers of antelope on public lands in Idaho if you know where to look. Furthermore if you do some good scouting your shances of harvesting are as reasonable as they can be with a bow. Try looking at unit 58 and hunting water in the area. Also try to contact landowners. I know plenty of farms up I-15 (I think they are owned by Larsen Farms) That have many antelope on them. If you could find a farmer with antelope problems and set up a blind in or on a haystack near water you should have good odds of harvesting.

Another option is trying to contact the INEEL and getting a waiver to hunt on the government land out there. My Dad works out there and says there are good numbers of large antelope. Furthermore this is a huge section of land with very limited hunting pressure. Again look for water.

By yhe way, I may sound ignorant but what is an OTR tag

OTC - over the counter tag

I ended up going to MT and while not successful I did get fairly close, 50 yards or so and had a blast the whole time, looking forward to my next hunting trip.