Generally, the purpose of a RoadTrip is to enjoy a bit of time on the open road, enjoy some scenery, enjoy stimulating the mind with the occasional stop at a historical or other point of interest, enjoy some time communing with nature, and just enjoy not having to grind out each day. Note the emphasis on the word 'enjoy'. That's one of the reasons we simply cringe whenever we see comments like "We can take turns and drive whole day." There's almost nothing enjoyable about being cooped up inside a car for an entire day, no matter how pretty the scenery passing by the window is.
So my first bit of advice, before and above answering your questions, is to make time each day for the purpose, for the enjoyment, of the trip. Assuming you take the inland Interstate route in one direction and the coastal PCH route in the other, you're going to need to actually be driving for about 35 hours or so over the week you have - or about five hours every day. Now, with a small child that already doesn't sound like a lot of fun, but maybe that's what you want. So my second bit of advice would be to work out a destination for each day of your journey now and make reservations so that you are not having to waste precious time trying to find a place to stay each night or worse, being turned away by one 'No Vacancy" sign after another at what is, after all, the height of the tourist season.
AZBuck