You could also cycle hah. Depends where you are in Yanchep. The Yanchep Central shops are now open so shopping for your everyday needs just got easier. Commuting to the city can still be a pain (50 mins drive) but park-and-ride from Clarkson to save yourself the hassle if you're working in the city. In summary, I'd get a runner car to get around the suburb and around.
Yes, pretty much! It is too far away from anywhere else to walk places - except the beach and the local stores if you are not too far away. If you needed medical treatment, had kids in school or pets needing vets in a hurry you would really be stuck. Major shopping is a fair distance, so you would need to travel quite a bit to get everything you need.