I travel part of this route fairly often and will be heading that way this weekend to Havasu. I usually go to Desert Center (hwy 177) when not towing.
In a motor home, I would recommend going up to the CA/AZ border and go through Ehrenberg if you have never done that. It's flat, straight and all farm land.
Through Yucca Valley/Twentynine Palms There is a pretty good grade to climb from the I10 up to Yucca Valley some stop lights but not much going on. No clearance issue that I can recall.
If you do go through Ehrenberg, there is a War Relocation Center (in Poston) where 17,867 persons of Japanese ancestry, the majority of whom were United States citizens were interned during World War II from May 1942 to November 1945.