Thanks for the suggestions. California has been one of our favorite destinations over the years. I remember our first visit and a drive down the PCH - watching people with their campers in tow around twists and turns so tight they could see the end of their camper from the tow vehicle!
Our destination is to Indian Wells, just south of Jushua Tree, near Palm Springs. It is one of the few parts of the state we've never visited.
Thanks for the suggestions about Texas and New Mexico. We're trying to decide whether or not we'll have time to visit the Grand Canyon again this trip. I guess we will make that decision when we are leaving California.
Question, how busy is the campground inside the GC Park in mid March? We stayed in Bright Angel Cabins the time we visited.