Suggest you plan another type of travelling

If you must bring your very young kids and your parents - there is no way you can handle the traffic in CA, be it LA or SF.

It sounds you hardly have much experiences driving Interstate, as well as major highways in big metropolitans. If you feel at home driving in Chicago, then I would think you can handle California. If your driving experiences limited to Des Moines and the kind, then you would be very scared driving California Highways, By-ways, and even local streets ...

GPS only helps you for the main directions, it will not help you for the small streets and that are supposedly how you would find your way around ... Near impossible in LA area and fairly difficult in Bay Area / San Francisco area, if you are relying GPS to navigate around the local streets - forget it.

Furthermore, it does not seem you have any help in terms of navigation - planning routes, alternative routes, reading maps (we prefer maps much more than GPS, as maps can really show the details and you can study it ahead of time and make notes, versus GPS will tell you to turn, regardless which lane you are, and you probably are at the wrong lane as you have not studied it ahead of time ... just my 2 cents).