Off the top of my head and taking the two year old into mix:
- Whitefish, Mt. The town is really nice and Glacier is minutes away. I stayed at The Lodge at Whitefish Lake. One of the guys that consults for us is best friends with the owner so we got a reduced rate. I spent a few days there last summer.
Amazingly nice setting. Fishing, water skiing, etc. Fly into Kalispell, Mt. You can also fly into Missoula or Great Falls and drive.
- Great Smokey Mountain National Park. I really enjoy the area but it will be hot and humid in the summer. Easy and cheap, however if you can get there early in the season.
- Maine. The North East is tiny so you can trek Maine or stay on a Lake/Sea Shore. The weather is excellent and there are any number of great side trips.
When the kids are older I have a different list