Kalispell, Montana sits in the northwest corner of the state close to both Canada and Idaho. This is one of the most beautiful places that I have had the opportunity to live in. Within relatively short drives from here you can see Glacier National Park, one of the largest man made reservoirs in the U.S., and miles of forest that make you feel like an explorer. Some people refer to this part of Montana as the Alaska of the lower 48 states.
Most people coming to Kalispell and the surrounding areas and towns are usually there to see Glacier National Park (during the summer season). Summer every year is marked by the official opening of the "Going to the Sun" road (after plowing throughout the spring and early summer months). Glacier is a very beautiful and popular attraction of the area and definitely something you should take in on your trip.
With how popular it is and everything there is to see and do in Glacier, traffic has become a real problem. I would suggest that you carpool your group as much as possible. Also, leave the driving in the park up to the historic convertible shuttle buses that run constantly through the park and make frequent stops.
If you're into hiking, Glacier has some spectacular ones and the views go on for miles. It is the epitome of outdoor adventure. Also keep in mind that Glacier National Park is mirrored on the Canada side of the border with Waterton Lakes National Park. Taken together, these two adjoining National Parks cover a vast, remote area that would take weeks to explore every available corner. Be aware that wildlife, specifically bears, are prevalent in the forests and parks, take proper precautions.
North of Kalispell is a small, yet exclusive, town of Whitefish. Whitefish is home to a ski resort, which is the source of most of the winter season traffic. Whitefish has some of the most expensive real estate in the area and caters to a more upscale crowd with its shops and restaurants. It is worth some time to look around the town and enjoying the atmosphere.
Big Fork is another town near Kalispell that is a must see. It sits on the shores of Flathead Lake, the predominant lake of the area. The town has kept its historic charm and is easily strollable from one end to the other in about twenty minutes. There are numerous shops and restaurants to check out, but the view at sunset is the real jewel.
Lake Koocanusa (actually a man made reservoir) is about an hour and half west of Kalispell near the small town of Libby Montana. There are numerous fishing and boating opportunities as well as some natural falls in the area.
There is so much to see and do it's tough to cover it all in one article, but most people will base themselves in Kalispell with its services and restaurants, and then spend a week or more exploring the area. However long you decide to stay for your vacation, it is a definite must see destination.