Generally in mid to early september,  you're going to want to be as high as possible where there is still a little bit of cover.  That means treeline.  Actual elevation depends on the local factors which form the treeline.  But once up there, you'll need to find reliable feed water and cover.  Given their druthers and in unpressured country, the flatter areas are usually better.  It's easier for the elk to move, and retains moisture better for better feed and water.  I really like small north facing meadows surrounded by heavy timber, but those are less productive during archery season.  In archery season you have a lot of mouths to feed (or you should), so feed quntatity and quality takes high precedence for me during this time of year.

Find the Aspens and you will find the bucks in that area, he is right about the north facing slopes

good luck

welcome to idaho. the replies are pretty accurate except for one thing.  the wolf.  alot of idaho the wolf is no big deal.  in other places it is a major objective to overcome.  Not becasue there is no elk.  Because the elk have changed their ways.  they are not in the open like they used to be.  They hold up in the timber.  The deep thick timber that no one likes.  the thicker the better.  In alot of areas of idaho, gone are the days of climbing to vantage points and just glassing.  If the wolf is not heavily present in your area, you can climb to the vantage point and glass.  So you have to change your way of thinking if the wolf is present.  also in areas that have wolfs.  the animals are bunched up.  a couple of big herds, versus a bunch scattered everywhere.

good luck and idaho still has lots of elk, you just have to take all things in to consideration.