Don't forget right now the Euro is about $1.60 US, so traveling here will be a bargain.

I suggest picking up a Lonely Planet or Insight Guide before you travel; those two should have some fairly current info on places to stay.

The US does not have the same well-developed infrastructure as Europe for train travel and other public transportation. It is pretty hit and miss, depending on where you are.

If you are camping, there are passes you can buy for the national parks that will get you into all of them. Even for a short trip, it may be worth it if you visit a number of them, especially if you hire a car.

Individual states have their own park systems apart from the national parks.