Yep. That I would grant!It is very easy to spend a month anywhere..OK. First night I would stay in St. George, Utah. Drive through Zion National Park the next morning and head north on US-Hwy 89. Hwy 89 has great views and moves nearly as quickly as I-15. (It is slower because of the cities and towns, but you will be OK timewise). Night #2 could be near Salt Lake City. The tour at Temple Square is worth seeing no matter what you might think of the the Mormon faith. From here, I don't know where in Montana you are headed, but I would probably suggest you push up I-15 to I-90 to your final destination. You may need to drop Temple Square and push on towards Pocatello, Idaho to make that third day more relaxing.unfortunately we will have to make do with two weeks... The big day is a wedding so we want to try and make the most of it and see bits that we might not have another chance to see..
Return trip: Let us know where the wedding is and we can share tips for the route back to LA.
Mark