We are planning an RV trip coming from UK. Last year hired RV and took 3 weeks to see San Francisco, Monterey, Big Sur, Yosemite, Sonora, Half Moon Bay..now we'd like to visit again but start in Southern California and see what is there then go to Grand Canyon, Zion National Park back to LAetc. Or not a loop but go from LA via Grand Canyon to Baltimore ( I have family to visit there). Is this a long trip to take with young children (4 and 7). Seems to be so much of interest along the way but not sure if 3 weeks too short. We don't want to be driving long distances every day. Or drive some of the way drop RV then fly to rest of way to Baltimore?Ideas appreciated, we are not going until April 2011!! but like to get rough idea of route now!