The Indian Heaven is in the Soiuxon unit # 572. I'm pretty sure there isn't a general M/L season there. Isn't there a permit only anterless hunt for the 572 in early October? Beautiful country, lots of meadows, huckleberry bushes, high lakes, old growth, etc. Before Labor Day the bugs can be bad and yes the trails get pounded by hikers. By mid-Sept most of them have left depending on the fall. Jackofalltrades is right about the weather. But heavy, here to stay snow usually comes late Oct or in time for rifle elk.
The perimeter country outside the wilderness is typical cascade forest. Old growth, 20-35 year old reprod. A decent amount of blocked roads either gated or bermed. Decent road access. Terrain isn't too bad until you move south into the creek drainages in the Wind river unit, north into the Lewis river watershed and of course west into the Wind river valley. I spend a lot of time spring to fall up there but my response is from a rifle hunters point of view. That's why I say I'm not 100% sure on the M/L thing up there.
