Now you are thinking of a trip to the Thorofare in Mid September of this next year. Good for you! Now will try ti help you out on your questions. Just to mention this, this is big country with all kinds of options for trips and loop hikes available. It comes down to just what do you want to see and experience. It is all up to you. You could also go out via the Pacific Creek Drainage, or swing east at the Thorofare River and go out to the South Fork of the Shoshone near Cody via Deer or Ishawooa Creek Drainages, go up to Younts Peak - across the Buffalo Plateau - and out at Brooks Lake. Many possibilities. But this time of year in mid September, you could see anything from sunny and warm weather to snow and cold. Now that Two Ocean Plateau - Fox Park - Big Game Ridge - and headwaters of the Snake River is really really nice country and hard to beat with especially at this time of year. Personally have been all over this area from May to October so here trying to help you out.
Now on to your questions .....
I know it can snow anytime, but would that be a major worry at this late in the season?
Now I have been back here in the Thorofare in the fall as late as late October. And it was both snow and sun. Generally this is indeed something to consider. Generally we can and usual do have some really nice Indian summers here in NW Wyoming in the fall. But there is just something about this time of year in mid to late September it seems. It seems as if in most years there is some storm which passes thru the area with bringing some of the first snow and cold to the area. This past fall was horrendous it seemed. It seems as if in most years when the Aspens turn, a storm comes thru and drops some snow on the peaks. But before this it is generally sunny, nice, and warm. But you have to consider the what if's at this time of year. As for myself, I would go for it. But I am not you and I live here in Wyoming with being used to the snow and cold. But also in this country, have seen snow every month of the summer thru the years at some point. But on the other hand, the aspens are golden, the fall colors, and the Elk are bugling. Have been in places behind Yellowstone Lake in the wilds where the elk bugled all night straight - really nice!
With hunting season about to start in the Teton Wilderness, will the outfitters and packhorses be jammed into this area the 10th to 20th or so?
Now the hunting seasons back in the Thorofare are Sept. 1st for Bow and Arrow and Muzzleloaders. Then Sept 15th for rifle. Now for the regular rifle season,it used to start on the 10th but they pushed it back a bit by my understanding to this 15th date.. Most of the outfitters back in here set up their hunting camps at the end of August, especially if they have some bow hunters in there camp. The low point for them is uaually a month earlier in Mid August between summer and the fall hunting season. Now days in the Teton Wilderness, there just isn't the huge numbers of hunters that their once where. By this I mean the private hunters, This info comes from various outfitters and forest service rangers thru the years. Onetime a outfitter said that the outfitting industry was now 40% down. There will be people on the trail if you do out via Two Ocean Pass and the Soda Fork Meadows to Turpin Meadows. But it should be nice. But it could be really nice and all by your lonesome if over Two Ocean Plateau and the Big Game Ridge. As for myself personally, I prefer to go into the back parts of Yellowstone Park at this precise time of year instead of going thru the Teton Wilderness. I personally am not a hunter. There are some places in the backcountry of Yellowstone.
Do you prefer this section of the Teton Wilderness over the South Boundary of Yellowstone?
Now I love it all!!! The Soda Fork meadows is one of my most favorite spots back in here. It is all about the season. Generally when going into this country, I hang out at the Soda Fork Meadows in the spring and early summer. Then the Thorofare. Then the High Country in the middle if the summer. Afterwards in the fall time of year, in the Southeast Part of Yellowstone. One can not do that country much in the spring because of the snow, snowmelt, and regulations, and such. There is many many a place I love to hang out in the SE part of the park at precisely this time of year. And when I get my hiking permit, it is like 3 or so weeks long. It is all nice just depends on which month it is - spring,summer, or fall. Mariposa Lake, Two Ocean Plateau, Fox Park and the head of the Snake River, Big Game Ridge, and Boundary Meadows are really nice also. I call the meadows near where Coulter Creek meets the Snake River Boundary Meadows and have been here often at this fall time of year. It is all nice. Just what do you want and prefer?
Would it be better to start at Turpin Meadows and end at Heart Lake or is one direction the same as the other?
Now it is all what you want to see and experience??? I have started hiking trips at this time of year for this whole country at the South Entrance or the Nine Mile Trailhead or out of Cody, etc. I have been on about every trail in this whole area and each has it's own scenery and what it uniquely offers. But am not a hunter so generally again I avoid the main trails in the Teton Wild. for the back parts of Yell NP at this time of year. Now each direction and trailhead is different. There are some publications out there on this area ... it is still winter. Do some research and think what do you want to experience? The whole area of SE Yellowstone NP, the Teton Wild., the Washakie Wild., and nearby surrounding country is over 2,000,000 acres of some of the most wildest country left in the lower 48 states. One thing ... if you go ... Enjoy It Bigtime!!!
If any further question feel free to contact me. I will be more then happy to help you out.
Wishing You the Best!