Campgrounds: Signal Mountain, Jenny Lake, Colter Bay, and Gros Ventre
Highlights: Beautiful hikes around Jenny Lake and a moose at Gros Ventre
Major Hikes: Lupine Meadows, Jenny Lake, Emma Matilda Lakes, Static Peak Divide
Highlights: Black bear and alpine lakes in Lupine Meadows
Tips: Emma Matilda Lakes hike was a bit of an 11 mile let down. No wildlife and similar views were found in our other epic walks.
Campgrounds: Norris, Mammoth, Bridge Bay
Highlights: Norris campground has a great atmosphere with a trail that takes you to some beautiful geyser activity at Norris Basin. We also woke up to a herd of elk meandering through Mammoth campground which was an awesome sight to see.
Major Hikes: Old Faithful, Grebe Lake, Mount Washburn, Bunson Point, Lewis Lake
Highlights: One way trek from Grebe Lake to Norris includes creek crossings across logs, lakes, ponds, pines, meadows, and we surprised a Grizzly! #adrenalinejunkie
Tips: Showers available at Mammoth... You can pay $4 at the hotel lobby, or not. No one checks. I also kept my cafeteria cup and enjoyed my free ice tea refills - it's the little things. Check out the thrift store in Gardiner (5 miles from Mammoth) - I purchased a Yellowstone t-shirt and a Patagonia fleece for $2 total! My friend found a wool sweater from Woolrich for 50 cents. Avoid Bridge Bay (and any campgrounds NOT managed by the National Park Service).
Overall, Grand Teton NP was my favorite. Every campground is beautiful and unique. The trails are out of this world. I would recommend spending most of your hiking time at this park and letting yourself get lost in the remote Teton ranges or meadows (just don't forget the bear spray!) and then going to Yellowstone for the "attractions" such as Old Faithful, the Falls, and geysers. Most of the tourist spots are less than a mile to check out.