The deserts are all different, too. There’s the “painted desert” in the southwest with astonishingly beautiful rock formations, and the achingly lovely desolation of places like Death Valley. The scrublands of Texas are awesome to behold because of their flatness. (The sky has never seemed so big or blue until you’ve seen the awe-inspiring sight of nothing in all four directions all the way up to the distant horizon.) In Arizona, you’ll see some Sahara-like dunes. (IIRC, one of these places is around Yuma.)
Some general advice about US travel:
If you want to see Hollywood-style “Old West” go to Bracketsville, Texas during tourist season. The set of John Wayne’s The Alamo still stands there, along with an “old west town” where a lot of movies and TV shows were filmed. They have shoot-outs in the streets, guys roaming around doing lasso tricks, an “old west saloon” with girls in garish costumes serving soda and various shows on the stage. As a kid, I thought it was a hell of a fun place to visit.
Avoid Orlando, Florida like the plague during summer. It’s fucking hot, incredibly humid and they have mosquitos the size of hummingbirds. In the winter, it can be a lovely climate, but I’ve been down there about half a dozen times in high summer and every time it was hell. (I’d imagine for a European, it would be even more miserable 'cause you guys ain’t used to it.)
If you want to see mountains, the Rockies are obviously the first choice, but don’t neglect the Smokies. Gatlinburg, Tennessee is a tourist-trap nightmare (though a European might get a kick out of seeing American kitsch at its zenith). Pigeon Forge is nearby, and a little less touristy, but still pretty bad. I always prefer to rent a cabin when I visit there to hide away from all of the noise and bustle and just enjoy the majesty of the mountains. (If you’re renting a cabin, be sure to search for one that’s isolated. Nothing’s worse than some of those cabins they cram together. It’s like you have the shrieking kids next door in your own cabin.) The best time to go, in my opinion, is spring (before May) and after September. Both of those times have better climate and it’s after the kids go back to school, so you won’t have lots of families clogging up the place. Spring is nice because you might get a late snowstorm, and fall is nice because of the changing leaves.
Spring is the best time to visit Washington , D.C., especially when the cherry blossoms are out. If you hit it right, you’re before the main tourist season, it’s beautiful, and the weather is nice. (Not too hot; a bit chilly in evening.)
I know it sounds dumb, but I didn’t expect **Hawaii **to be as hot as it was. For some reason, I always pictured it as a lovely 72 degrees. Instead, I discovered that Lahaina is aptly named. (“Merciless Sun”). Conversely, I froze my ass off in the mountain areas and had to buy a jacket.
Priceguy, Alaska is hot in the summer, unless you go up into the high mountains, of course. It gets hot enough to qualify as “miserable” in high summer, and the bugs are atrocious. If you go in late spring or fall, you’ll probably be there in a nice, temperate climate.
If you want to see Small Town America, go to Indiana, Illinois and Ohio. (Especially southern Ohio.) For the Southern version of Small Town America, visit rural Georgia or South Carolina. (But not in the summer! Too hot! Too hot!)