I live in Idaho as well!
This is for sure a Great Horned Owl. I hear them do this all the time, generally the females do it I think. Also their ear tufts can be hard to see sometimes, especially as it gets dark.
I hear a duh-da duh-da duh-da duh-da towards the end of the video. Sounds like a Chickadee scolding (I think) but I don't know if that's what you're referring to.
Oh nice!
It's about 4 hours from the Utah/Wyoming border to the South Hills. It's a long jaunt but it's worth it! You could stop at Antelope Island State Park as well. Are you camping along the way or staying at hotels?