Color me jealous. Would love to take a chunk of time and just drive around the country seeing shit.
If/when you make it out to California, check out the Eastern Sierra/Highway 395/Owens River Valley part of the state. Most people head for LA, SF, Napa, Highway 1, San Diego, Santa Barbara, Disneyland, Yosemite, and all the other touristy areas of CA. But the Eastern Sierra is one of my favorite places in the state. The scenery is great, and there are several off-the-beaten-path places to explore.
Check out Bodie, which is a mining ghost town that has been preserved and is now a state park. It's a cool place to walk around and explore. There's Mono Lake, with its weird-looking tufas. The area around June Lake and Mammoth Lakes is gorgeous. Take your RV on the 203 through Mammoth Lakes and go see Devil's Postpile. Lots of hiking in that area.
South of Mammoth Lakes there is more great hiking, fishing, rock climbing, etc. Stop in Bishop for a sandwich at Erick Schat's Bakery or Mahogany Smoked Meats. Or at least some jerky at Mahagony.
South of Bishop is Big Pine. East of that town, up in the White Mountains, is the Ancient Bristlecone Pine Forest. Do the Methuselah Loop hiking trail and by the end of it you'll be able to say that you've laid eyes on the oldest known and confirmed living non-clonal organism in the world -- one of the trees on that loop is the old guy (the park and rangers won't identify the particular tree for fear that knuckleheads will vandalize it). The road getting up to the forest is narrow and even unpaved at the end, but I seem to recall seeing RVs on it. Check with the rangers first to make sure I wasn't imagining things.
South of Big Pine is Independence. Tiny little town with a big Neoclassical courthouse -- where Charlie Manson had his first prelim after getting arrested in Death Valley for possession of stolen property and vandalism after the Tate/LaBianca murders. Across the street is a cool old hotel (the Winnedumah).
South of Independence is Manzanar NHS, where Japanese-Americans were interned during WWII. Well worth spending a few hours there.
South of that is Lone Pine and the Alabama Hills, where hundreds of movies have been filmed over the years. It's easy to drive around the Hills and admire the scenery, which includes Mt. Whitney. There's a fun little film museum in town, which of course focuses on the films that have been made in the area. Alabama Hills Cafe is good for lunch.
Southeast of Lone Pine -- if you head toward Death Valley NP on highways 126 and 190 -- you can see The Joshua Tree shrine just off Highway 190. Even if you're not a fan of U2, it's kind of fun to park just off the highway, traipse about a quarter of a mile (or less) to the south and find the shrine. U2 fans have left all kinds of stuff at the site of the joshua tree that was pictured on the 1987 album. (The tree itself is down.) Kind of a fun thing to do; a bit of a challenge to find, but not too hard. I wouldn't try to do it now, though, with temps around 120-125 degrees in the afternoon in that area. Wait until late October or November, or the spring.