Steph is (mostly) from Montana and Jeff loves Montana - it was one of the things they first bonded over. So they figured they would equally inconvenience everyone, including themselves, by getting married there!
The same thing you would wear to any other wedding. No need for black tie, but maybe save the Chacos for Friday or Sunday. If you wear something dressy casual that you are comfortable in, you will probably be in the middle average of the attire spectrum. At least one other person will be wearing a dress.
Had to google dressy casual because even as it was typed, it was unclear if it was what was intended. Per Cosmopolitan, "it’s a way to describe an overall aesthetic that is basically not-all-the-way-formal-but-please-don’t-wear-jean-shorts".
Weather in early June in Montana is a mixed bag. Could be 70s during the day and 50s at night, could be snowing, could be raining... check the weather in the week leading up to your travels to make sure you are prepared with the right clothing. It could definitely drop into the 40s at night as Montana late spring evenings are generally quite cool.
If you have found someone who wants to travel to Missoula, Montana with you to go to a wedding, then you are basically obligated to bring them. Maybe it will also cut down on the amount of bored phone scrolling you do. Just make sure you indicate this on the RSVP for planning purposes.
Kids are allowed at all of the venues throughout the weekend. So if you really want 'em there, bring 'em! Please indicate number of kids in your RSVP for planning purposes and you're responsible for them.
Each wedding guest will get two complimentary drink tickets for the evening....... just kidding! Not sure why this is even an FAQ. There will be beer and wine aplenty. Another thing about getting married in your 30s is that it's really too painful the next day to hit wedding open bars too terribly hard (we hope).
Turns out when you get married in your 30s (and soon to be 40s *cough* Jeff *cough*), you've already managed to accumulate far too many things. What they want most for their big day is to celebrate with the people they love. If you feel so inclined to give a gift, you are welcome to contribute to the Braune Homestead fund.
Montana is spread far and wide so expect some travel time if you want to go explore other places. For reference: Missoula to Glacier National Park - 2.5hrs (140 miles) Missoula to Bozeman - 3hrs (200 miles) Missoula to Yellowstone National Park West Entrance - 4hrs (260 miles) Missoula to Butte (IYKYK) - 1.75hrs (120 miles) Missoula to Helena (state capitol) - 1.75hrs (120 miles) Missoula to Banff, Canada - 7.5hrs (400 miles) Missoula to Flathead Lake (Polson) - 1hr (70 miles) Missoula to Quinn's Hot Springs - 1hr (70 miles) Missoula to Big Sky - 3.5hrs (240 miles)