Something to keep in mind if you do plan on going to Glacier National Park in an RV, you may miss out on driving one of the most scenic in roads in the country, the Going To the Sun Road. There are restrictions on the size vehicle you can drive:
You could park your RV and take one of the red jammers tours or there are shuttles that will take you from the east to west side of the park. Sounds like a great trip for the family!!
[ Edit: Sorry, no promos please. ]