dgwright99

Welcome to FT !
I grew up in the UK, and live in CA, so I have, perhaps, something of a transatlantic perspective on your question.

For most Americans, 10 days is quite a long vacation (holiday), and Americans tend to be a lot busier on vacation than Brits. Of course that';s a generalization, but the OP may want to consider thaose factors when reading advice from the locals (FWIW - personally I take the American approach).

First off - Trailfinders are good - my parents use them, and I'm rarely able to come up with anything cheaper.

Finding places to stay will not be a problem. If you give us an idea of your budget, there will be plenty of people able to give suggestions on hotels. If you are on a modest, but not tight budget then Holiday Inn Express hotels are usually reasonably priced ($70-100) and consistent, so you know what you are getting with no surprises - and they are everywhere, and you'll often have a choice of half a dozen within a few miles. Courtyard by Marriott and Hamton Inn by Hilton are perhaps a shade nicer (and more expensive) and also good options if what you are looking for is consistency/predictability. If you are looking for something cheaper, Red Roof Inn are better than the other big motel chains (eg Motel 6, Super 8); I'd avoid Travelodge - although it's a familiar brand in the UK, there are some real dumps over here.

If you are not going to be able to come back again within a few years, then I think your idea of waiting until you can spend 2-3 weeks is probably a good one. 10 days is not going to be enough time to see much of CA. If you are likely to be able to come back in a couple of years then your idea of just seeing northern CA ("NorCal") on this trip is a very good one.

Other things to do on a longer or second trip are Las Vegas and Grand Canyon. Many people (eg my British in-laws) expect to hate Vegas, and end up loving it, and IMHO everybody should go out of their way to see the Grand Canyon if they come within a thousand miles.

So, for a low-stress 10-day CA vacation of the kind you mention, I suggest spending the whole 10 days in Northern CA (ie fly in/out of SFO). San Francisco and immediate surroundings ("the Bay area") will keep you busy for at least a week. Add in wine country and Yosemite and you have a well-rounded, not too busy but plenty to do 10-day holiday.

A few tips:
In San Franciso, I wouldn't have a car the whole time. Many hotels charge for parking and the traffic in the city itself is awful, and public transport is good. (And I say this as a stereotypical car-lover who drives a huge SUV, and very rarely uses public transport - except in places like NYC and SFO). So if you plan to spend a few days in the city, then head out to wine country and/or Yosemite, I'd seriously consider leaving the car until the day before you head out of the city.
If you prefer small, independent hotels to the predictability but blandness of the chains then you'll get heaps of suggestions if you ask in the San Francisco forum http://www.flyertalk.com/forum/san-francisco-468/ www.tripadvisor.com is also a great resource.
If you plan to drive long distances, consider an SUV or minivan (people carrier). The driving position is higher and more natural, so you get a much better view of the scenery, and driving hundreds miles is no more tiring than driving for a few hours in a car.
See if you can rent a car from a non-airport location - it will be cheaper, whether pre-paid (which I recommend - eg www.holidayautos.com or via trailfindfers) or a conventional booking.
Remember that in the US prices are quoted exclusive of tax, and tips of 15-20% are expected in resteraunts (not fast food).
It's worth getting a credit card with low/zero foreign exchange and transaction fees - I hear from family that most UK credit cards now have these fees - and fees of several pounds per US transaction are not uncommon. So, it can really pay off to get a new credit card just for this holiday, even if you cancel it shortly after you get home.
Don't book hotels via a travel agent; very rarely will they get you a better deal, and very often you'll find it cheaper on the hotel's own website, or on Priceline. Priceline has great deals on hotels, and if you use it carefully, you can often figure out exactly what hotel you'll be getting even when booking "name your own price" bargains.Also, consider making some reservations flexible - so you can cancel up to the day of arrival, especially for those days when you are away from the city.

I lived just outside Yate for a while in the early 90s !