WOW! Thanks for the numerous and quick replies, so many more options for us to consider.
We intend to go in a couple of weeks over Christmas break. I figured we would make a reservation on an open night and get in the car and drive.
Didn't know about Julian - we'll have to look into that as well as Rancho Bernardo --- both areas around SD that we haven't explored.
I hadn't thought of using Palm Springs as a jumping off point for Joshua Tree. We have been to Palm Springs, but it's a really good idea with the expanded option of JT and the zoo! Might even bring the grandparents again so they can sit in the saunas.
Thanks for the votes for Big Bear and Arrowhead.
All good options for us to consider now!