I don't think I can give you much help on selecting the RV that is right for your lifestyle, but others seem to suggest renting several types of RV to get a feel for what suits your needs the best.
I do think that your idea about traveling as a musician is a great way to go. After all, music is the universal language and you will be a welcomed addition to any place you set up camp.
I always travel with several guitars (there is always a player who doesn't have one handy) and also some small percussive instruments. The idea of having an informal traveling group of musicians sounds like fun.
Since you are in California you may be close enough to the Imperial Dam Long Term Visitor Area on the Colorado River to pay a visit. There is an area called Music Row
that may be just what you are looking for.
Best of luck with your plans!