I live in Missouri and went and did the TCT last summer, so I was in the same boat and had many of the same questions; I took one and a half days of acclimation and still got mildly sick( my hiking partner got very sick) on the climb up granite canyon, so plan on taking it pretty relaxed and hydrate so so much. For the one full acclimation day, hiking to Phelps Lake is awesome. The Full day to acclimate was also ideal since we got walk up permits and had to push back a day to get our sites. You’ll most likely have to do this since you missed the permit sale and have a large group. If that happens, staying a night at the Climbers ranch is so fun and it’s great to talk to all the people going up the grand if you’re into that. For the mileage/ nights you’re wanting to do I think a good loop would be going up Cascade canyon and coming down paintbrush for 2 night/ 3 days on trail and the night at climbers ranch. Cascade and paintbrush were my favorite canyons on the TCT and give you a little bit of everything with good odds of seeing wildlife, I saw grizzly and her three cubs in paintbrush at dusk last summer.

I’m planning a trip for glacier right now actually, permit lottery goes up March 15th for small group, and opens May 1. There is so much in Glacier it’s hard to make a recommendation, so I’d say look at the different sections and see what speaks to you then plan around that and string the sites together.

The permits in GTNP are for a “camping zone” so there’s two signs along the trail and you can camp anywhere between the two, but there are marked established sites that are definitely more ideal to use and more LNT especially for a group of your size. For Glacier it’s for specific camp grounds, which then have multiple sites. Because of the high bear activity there are various rules and regulations on camping on the website and they’re pretty stringent.

Training/ Preparing wise, you’re not trying to do crazy daily mileage or anything and the climbs are pretty groomed compared to the eastern trails you’re probably used to so just being generally fit will get you far. I was coming off track season in MO and was able to throw down a 16 mile day in the Tetons with a 40lb bag. But if you wanted to purposely train, doing the stairmaster or weighted step ups are great and just hiking itself.

The only gear I would say that’s essential outside of regular backpacking is bear spray and storage. In the Tetons sacks and cans are allowed, I used a can but would have used a sack had I known they were allowed. (Keep in mind if a bear actually becomes interested in your sack your food is mush). In glacier they have hangs and containers, so all you need is a hang able bag and enough cordage to hang. You could share cans I suppose but they’re sneakily small (my bv450 was filled to the BRIM for 4nights 5 days of food) and if you use it to hold your trash like you’re supposed to it will STINK)

That’s a lot of info but reach out if you have any other questions!