Travel
Idaho Falls, Bozeman and Salt Lake City are the 3 main contenders for airports in the area. Idaho Falls is the closest, Bozeman is a bit bigger and may be easier to fly into for some. I would recommend a direct flight if at all possible even if the airport is further away from the venue.
If you are able to coordinate flights with other members of the wedding, you can group rent a car which may make up the cost difference. If possible, I would also recommend a vehicle with all wheel drive, the road to Riverfront Retreat should be filled in but does get bumpy from the snow.
We have enough beds at our venue to sleep most of our wedding party (arrangements will be provided), but a few of our guests will have availability to stay just down the road at The Pines. You should see it on the way into Riverfront Retreat.