Glacier is my favorite National Park. I've been there a number of times, in fact, my daughter got married
on the shore of Lake McDonald & had her reception at the group campground at Apgar.
While I've stayed on both sides of the park, I prefer the West. Still, my favorite campground is Two Medicine, although it can be difficult to get into since it is first come. Apgar usually has empty sites as long as you arrive early. You can check the average & daily fill times for any of the Glacier campgrounds at the camping status page
. Click on the campground & check at the bottom of the page for fill times.
Where ever you stay, be sure to drive out to the Polebridge Mercantile on the West side for a sticky roll or cinnamon bun. A great bakery!
I have a page of photos of Glacier during a 2011 trip here