If you're in California, the train ride between San Diego and LA is really cool. It goes right along the coast. It's clean and seemed to keep to schedule fairly well. You can buy tickets from a person in big stations and from machines everywhere else. I love trains! But… the US is really a car country. Amtrak has some nice long distance tours, but you can probably do much more for cheaper in a car.
It's really hard for me to come up with recommendations, and the US is my country. The nature out west is amazing, but Peebles is right about New England--off the beaten trail is really wonderful. A little further south, I used to drive from Baltimore to Oxford, PA, to visit my aunt. This goes through Amish country on back roads. I always loved that drive--rolling hills through farmland mostly. Annapolis is nice, too, and the museums in DC are good. If you're in Florida, Ft. Pickens near Pensacola is really beautiful.
It's really hard for me to come up with recommendations, and the US is my country. The nature out west is amazing, but Peebles is right about New England--off the beaten trail is really wonderful. A little further south, I used to drive from Baltimore to Oxford, PA, to visit my aunt. This goes through Amish country on back roads. I always loved that drive--rolling hills through farmland mostly. Annapolis is nice, too, and the museums in DC are good. If you're in Florida, Ft. Pickens near Pensacola is really beautiful.