Doing a West Coast tour and San Diego is our mid stop for 4 nights. I fancied an air bnb so I could wash clothes, relax, have more space but most seem to be in town rather than on coast and very expensive. It is a holiday of a lifetime but is already costing thousands. 2adukts, 2 kids.
San Diego is ridiculously expensive. If you’re on a budget it might not be the best choice but if the plans are that you stay there a few nights then even motels will have laundry facilities, if that’s the priority. If you want something more home-like then it’s not going to be cheap there. Curious as to your itinerary if San Diego is the halfway point. Are you traveling from Mexico to Canada? Sounds like a great trip!