What do you mean by rule of thumb? Like what should you do? Depends on how far away the bear is. If close and they don't know you are there, you leave quietly. If close and they do know you are there, you leave quietly and slowly. If far away, enjoy watching them, and consider yourself lucky to see the apex predator of the lower 48. If possible, I find a spot to watch the bear from a distance and decide what I'm going to do next.
The main thing is to put distance between you and the bear.
Do a search on here to read about dealing with a downed animal in bear country. For camp, follow the clean camp guidelines put out by the FWP. They cover what you need to know and how to do things.
If you see a wolf, shoot it. No one has mentioned a wolf tag, get a wolf tag regardless of which state. If you need one, not sure on Idaho's wolf tagging requirements.
Consider a truck camp for your first couple of trips. 4-5 miles in is a commitment to that spot. You really need to know there are elk there to make that kind of commitment. Also, a 5 mile packout in the mountains is not for the faint of heart. I would highly suggest you not go farther than 3 miles if alone. When I solo backcountry camp, I do the packout in two days. Day one to camp. Day two to the truck. Camp is no more than 3 miles from the truck and less is rough country.
Montana is an every other year tag draw generally speaking. Idaho is OTC, but more limited on where you can go on the OTC tag. MT is wide open on the general tag except for a few units. Both have elk, the rest is up to you.
Jeremy