I have hunted a lot in the Elk City (east of Grangeville) area which is not far at all from the Selway. I have pulled a few bulls out of the area. The area is real steep, but the forrest is not real dense like you see in Western WA. I found it to be a big advantage to find a higher ridge with a good saddle to scope. The elk tend to go down into the deep black timber during the day since it is still pretty warm in North Central Idaho in October, but come up out in the higher openings as the day cools off. It is common to be 65 during the day, but 22-25 at night. You might find the bulls in the black timber during the day, but take a frying pan, like I said, it is STEEP. I have not been back to Elk City for about 4 years, since the wolves have taken over. The last time I was there, we had wolves within 100 yards of our camp at night, howling and growling- I kept my .357 close at hand. I find it a bunch of BS that the libs think the wolves are a good idea in any shape or form. There used to be over 13,000 white tail that migrated through the panhandle of Idaho each year, but the wolves have gotten so bad, the numbers have almost been cut in half.
I don't mean to put any damper on your hunt, I think the northern Selway should still produce some fine bulls, but maybe just a heads up especially if you have horses.
I have a life time license in Idaho and go back each year to hunt elk. We will be in the Stanley area this year, however the wolves have made it that far south now as well.
If you call a bilogist in Boise at the Dept of Fish and Game, they should be able to provide some good insight for you.
-Good luck with your hunt!