Suggested Locations

I am in Perth, new to WA and would like somewhere I can go for a few days, before I flip, set up the tent with the family etc and relax... (aka become human again)

Ideally I would like somewhere near the coast, secluded, 2wd access where the dog can come along, within 4 hours drive or so...

Any suggested secret locations that can be recommended would be greatly appreciated ?

Thanks in advance...