Two years ago we stayed at the West Glacier KOA. They have both wooded and open pull-thru sites. We stayed in an open site that was on the end of the row, very level and clean. They also have a little resturant that was nice to eat at for breakest and dinner. Just down the road toward the park on the right is another nice place to eat. I had the 20oz ribeye for $10. Could not eat it all, but very good.
I would strongly recommand that you take the red bus tour of the park. They picked us up right at the KOA. Spent the day on the "Going to the Sun" road and back to the KOA. Another camper was staying down the road at another place and had to drive his rig to the KOA to get the tour. The "going to the Sun" road is limited to 21 foot long vehicles, except for the red buses.
Takes lots of pictures and enjoy yourselfes.