Buy some diaphragm calls. Find what size fits your pallet and practice in the car going to and from work. If you do go solo and call a bull in, he will know exactly where you are. Having the ability to call while your release is hooked up or at full draw is a huge help in the solo game.
The best strategy I've found for hunting Idaho is to hunt OTC archery units that are limited draw for rifle. It allows you to learn the unit when you're there with a bow and have it dialed in by the time you draw a rifle tag.