If you get the chance checkout western Montana and Idaho. Both beautiful places, the Coeur d'Alene area is very nice. If you get to northwestern Montana the Flathead valley is also beautiful. I would recommend a drive around Flathead lake and a trip into Glacier National Park, although depending on what you are driving the Going to the sun road can get a little scary.
Always tons to do from river rafting to hiking & fishing. I would also recommend a trip to the top of Big mountain ski resort, you get fantastic views of the valley to the south, views of mountains to the north and Glacier Park to the North east.
Whitefish Montana was my home for 10 years and hopefully in another 1 - 2 years will be again.
Wherever you decide to go I hope you have a great time!