Choosing a campground is risky - you never get the real scoop until you experience it yourself. Here are some pearls from my log:
We camped at Yellowstone and Grand Teton 2 yrs ago. In Yellowstone, we camped in Canyon Village, a nice campground - also a convenient spot for doing daytrips around the loop of the park. We were there the last wk of June and it was very cold for a couple of days with some snow squalls. You'll see more wildlife in Yellowstone than you can believe. We stopped at a picnic area for lunch one day and a bear decided to join us....ambled right up to within 50 feet of the table! Don't forget to drive up to Mammoth Hot Springs up in the NW corner - it's amazing.
In Grand Teton, definitely camp at Colter Bay - pick a nice high campsite and you'lll have the most breathtaking views - that was my favorite campsite ever - if I remember correctly, we were in Loop D. Look for it. Showers and restrooms are fine. We rafted the Snake River and it was rather tame, but the trails were gorgeous.
At Glacier, don't camp at St. Mary - it's too close to the road and too public. We camped at Avalanche campground for 2 nts (no showers, NO lights in the restrooms - bring a lantern; Mediocre campground) ; 4 nts at Many Glacier (showers and laundry available within walking distance at the Swiftwater Current Motor Inn - no lines at all) ; 1 nt at Apgar (very crowded and mediocre). The only public showers in the park are at Swiftwater Motor Inn (see above) and Rising Sun Motor Inn (near St. Mary). Buy shower and laundry tokens at the inn. Also at Many Glacier, there are ranger campfire talks everynight, and, if it's raining, the Many Glacier Hotel (about 1/2 mile away) holds ranger-led slide presentations every night as well.
Many Glacier is definitely the most scenic spot, with wonderful trails, horseback riding and lots of ranger-led activities. My 8 yr old son spent one morning with the Junior Ranger Program - he loved it. We also went on two 10-mile hikes....one with and one without a ranger guide. Go with a ranger to Iceberg Lake - it's a spectacular hike. We saw the most wildlife at Many Glacier - spotted 11 bears, 1 moose, mountain goat, bighorn sheep - and we heard wolves howling in the early morning. BELIEVE everything they tell you about the bears...we came upon a mother and 2 cubs on a trail. There will still be snow up on Logan Pass....skiers were on it last week. Be sure to hike up to Hidden Lake over the snowfields.
The weather was beautiful 5 out of 7 days - we drove to Waterton on one rainy day (about 1-1/4 hr from Many Glacier) and just walked around the town and up to the Prince of Wales Hotel. There was quite a bit of flood damage up there.
The Going-to-the-Sun Road was beautiful, and not very crowded. I was surprised to find out that the Park has again reduced vehicle length to just 21 feet, so there weren't any RVs on the road. There was alot of water runoff along the road last week, and we had a bit of fun with my son......when we would come upon waterfalls onto the road, we'd drive really close to it and let the water splash him in the car.
Lastly, be sure to take the kids whitewater rafting in West Glacier - I was somewhat apprehensive about taking an 8-yr-old, but it was quite safe, and tons of fun! If we hadn't left it until our last day, I would have gone again.
