Edit:I see this is an old thread revived—Oh well!
Re: time of year: Grouse are in broods until early to mid october depending on where in the state—usually around columbus day. Brood dispersal is a thing, the broods always 100% disperse as a hard-wired genetic tool to avoid becoming inbred. Early season you can have amazing days if you bump into several broods, as each group can have up to a dozenish birds…reload fast, there’s usually a few more birds in the group. but you can also walk a long ways through prime cover without seeing a thing. Plus with the leaves on there is food and cover literally everywhere so birds could quite literally be anywhere, and sometimes you cant see much, it can be frustrating if you are scouting and hunting at the same time this time of year.
After the broods disperse, birds are generally more spread out in areas that look more like distinct “bird cover” in singles and pairs. You usually dont get the big explosion of birds, but the action can be steadier, one here, one there, etc even without harassing birds by repeatedly following them up.
late in the season—say, after 100% of the leaves are down and there has been several hard freezes to kill back any ground cover, but before there is more than a couple inches of snow, usually after halloween or so— food and cover are both much, much harder to come by. This is killing season, everyone else is deer hunting so you have the place to yourself as long as you avoid parked trucks, birds will be concentrated around food, and you can generally see as well as possible to shoot, you can cover ground without sweating, etc.
If I could pick one time of the season to hunt it would be late. But without a dog and not knowing my way around, probably the third week of october. Also, regardless of time of year, without a dog I would avoid vast clearcuts or monotonous aspen cover and concentrate on linear edges along cover transitions—ie the thick strip along twitch trails, streams and alder runs, swamp edges, the perimiter of clearcuts, etc. with some evergreen growth nearby. that way you cover the highest-probability areas with the minimum of walking. Can be hard to find sometimes in areas that are mainly industrial timber. Sat images are your friend.