Went from west San Jose to Orange County to Vegas in early July. Model X P100D with 2 kids (youngest is 4). The following some of the Superchargers we used and why they were chosen:
Kettleman: Private lobby and cleanest bathroom along I-5. We either pickup food nearby or bring our own food and eat in the lobby. You can keep an eye on your Tesla while parked. Play wall in lobby for little ones to check out and everyone can stretch their feet. Tesla coffee and Tesla swag that you can check out and even try on. I clean the windshield while here and a tire air station is available. If you haven't already guessed we use this as a long lunch stop.
Santa Clarita: It looks far from I-5 but it is only 2.9 miles on a fast (minimum 50 mph) and wide road. Nice area and shopping center. We stop here to avoid the busier LA Superchargers and for a quick bathroom break. I-5 can get backed up in front of Magic Mountain so going here can help you avoid some of the traffic.
Yermo: Eddie's World can get busy from all the ICE traffic, but the most Teslas I have seen at the Superchargers is 4. This is another good stop to clean the windshield. Clean and efficient bathrooms, if you see a line don't worry it goes fast. Walk around and check out the products, the variety is crazy.
Las Vegas Blvd South: Definitely the better of the two stops in Vegas. Nice large shopping center. We went here when the car was unloaded and had dinner at Lazy Dog. Yes, it is the same Lazy Dog chain that is at the Cupertino Supercharger. There is also a Fleming's, Bonefish Grill, and Texas de Brazil that you can see from the Supercharger.