San Francisco / California driving holiday - any recommendations?

[Raider]

In September me and my GF are planning a circular driving holiday based around San Francisco. We aim to go for 14-16 days, and stay at 4 or 5 places for a few days each (rather than driving large distances every day and stopping somewhere different every night).

So far we're looking at something like:

5 nights in San Francisco
2 nights up in Napa Valley
2 nights around Lake Tahoe
4 nights around Yosemite
3 nights in Monterey / Big Sur (to see the best of the Pacific coast highway)
Back upto to SF to fly back.

We don't want to drive huge distances to go to Vegas, LA or Death Valley, preferring to stay within a 200 mile-ish radius of SF. I'm looking for any suggestions for cool places to visit around this area, or suggestions for an alternative route? Yosemite and Monterey are kind of fixed, but open to any other places?

Also we're looking to do the cliched thing of hiring a convertible, but sadly the main option is a Crysler Sabring... anyone know a rental place that can guarantee a Mustang or something a bit more interesting?

Ta!

 

[Raider]

Well it's only an early plan at the moment, and yes I do realise that'd we'd be doubling back a bit with the Big Sur bit. Also we might only do 4 nights in SF.

I guess I just figured that I don't have too much desire to see LA, so thought I'd avoid venturing too far south. But I'm not ruling anything out, if people can suggest nice places to stop on the way down! Maybe we could fly out of LA international, not sure.