I just noticed you're going to be riding 89 southeast of Great Falls. One of my favourite places to stay is Bob's Motel in Neihart, in the Lewis and Clark Forest. It's pretty basic, with reasonable rates, but it has a nice bar on the lower level, where all the locals go to hang out - a very interesting place.
If it's raining, Tony, the owner, will let you park under the staircase, around the back.
We're now up to 17 people coming in from all over the place. I'll give Tony a call and see if he handle 17 riders but I'm thinking that I'm saving this for trip #2. We've also moved the trip from Great Falls to Helena which will gives us more time in YP and Tetons mid-week.
Will probably break the riders into a few groups. I led this same group for the Eastern trip we did last year from Chautauqua NY to Barber Museum via BRP, Back of the Dragon, and WV routes that I know well and are gems...... It was too much as a single group for me - I was exhausted afterwards managing that many riders....
After this trip, I'm gonna stitch a week's ride out west.........
Tony should have lots of room in September. BTW there's a restaurant there too. I always stay at Bob's when I go to the Beartooth.
A final tip: you're going to be riding through the "Mid Continent Fuel Gap" between Great Falls and Harlowton (on Hwy 12) so make sure all your guys gas up at the latter when heading west. If one of your people get low, there is a big Sinclair at White Sulphur Springs, and it's only a short backtrack from 89 to there. I've had a couple of close calls with low fuel in that section.
Also, regular is available from Tony, and at Monarch, just north of there.
Keep an eye here:
Right now, Lolo Pass road on the Montana side is completely closed and evacuating. The town is at risk. Hwy 93 is a mess due to diverted traffic and fire fighting traffic. There is no possbile detour; the guidance simply is Take Alternate Route.
Beartooth Pass is closed due to fire, too.
Yellowstone has fires at Gardiner.
You might be a few weeks out, yet, but your intended landscape is changing before you leave.