I've never hunted Idaho, but I'll be as helpful in a general sense as I can. If it were me, I'd base when I hunted them this way: If I want to backpack in somewhere and hunt the backcountry, I'd go as early as I can. If I'm car camping, I'd go later and let the "opening day rush" wear off.
Either way that time of year, bucks are in thicker cover more than early September or during the November rutting period when they're looking for hot does.
The same deer are in the same general areas, the good ones just don't spend much time STANDING out in the open. They're there, just much harder to find. Bigger bucks lay down at the first hint of daylight, and don't get up until about the time you're thinking you're out of shooting light.
In early October, I'd find an area that holds some does and small bucks, then hunt above them to start. Deer like the same kinds of feed and water sources, so the bigger bucks are probably somewhere nearby, just not dumb enough to hang with deer that graze out in the open during daylight.
Get on a ridge that allows you to see a lot of country and look at every little spot slowly. look under trees, against rocks, and right out in the middle of the open for deer that are lying there still. I am always surprised at where bucks bed for some reason. Every time I think I have their tendencies figured out, I see one bedded somewhere I never would have thought to look.
If you're in canyon country, glass one area for a while, then sneak over the ridge to the next drainage. If nobody's bothering them, they might stay up feeding a little longer.
Hope this helps at least a little.
good luck.