Very smart… I tried to start in mid-June but was denied a permit because the campgrounds were in mid-meltout. You can take the antique park buses from the Amtrak station I think over to 2-Med to get your permit (get there early enuf to watch the bear movie). It cost about $6 each way a decade ago, but a bit more if you caught a guided tour bus that stopped at Trick Falls. Hopefully you can get a permit online now, because of the campground situation, I had a 10 mile day then a 30 mile day! Needless to say, I stealth camped on the 30 miler.
If you can, catch the campfire shows at the campgrounds!
Personally, I did my 1st flip-flop, hiking North from the Butte area… from Butte, or Whitehall where I actually started, several Greyhound buses a day go to Bozeman which was a much better resupply & place to stay. The hostel w/kitchen was centrally located (motels with internet also near main drag) & there was a health food coop for bulk foods (I like the instant soups). There was several outdoor sports stores along the main drag (a used equip shop was within walking distance of the hostel). The “Leaf & Bean” had live music nearby & library had free internet. Safeway was next to the COOP.
I sent boxes to E. Glacier & Lincoln from there. Then flipped by G.Hound & sent boxes south from there as well. I would drift or forward half of each box about 2 weeks ahead, I call this the leapfrog because 1st you get a double box, then a forwarded small box. I did the same thing in Denver, only SB from there. I shortcutted the Bitterroots south from Whitehall, thus I can only claim to have hiked the RMT or Rocky Mtn Trail ! Of course, a bunch of us shortcutted the San Juans because there was 3’ of snow up there, & only 3" of snow on the creede cutoff in early October. We were pretty flexible, because if you try to do every foot of the Divide, there is no way to make it except on snow shoes. If you start at Chief in early July, you probably won’t need any kind of crampon; can’t say the same for a Canada start! Good luck trailers.
inchworm plumber