We live in Northern CA and hit
Disneyland every few years.
When we fly, I just take a cab to/from the airport. Once at your hotel, if it is near Disneyland it is probably either within walking distance, or is on an ART shuttle bus route. Over on the DL board, lots of people complain about ART but if you are used to WDW buses, they really are just like them. The hotel we usually stay at is not in walking distance so we always use ART, and I'm fine with it. The shuttles costs a few dollars per day per person, but its easier and cheaper than parking if its just two of you. Most hotels in the area charge for parking, so using cabs/ART also reduces that cost.
BTW - Fly into Orange County if you can, not LAX. Easier airport to navigate, easier drive to Disney.
Our first few visits I didn't get Park Hoppers, and we didn't need them. It's easy these days to fill your day with just one park. That used to not be the case - CA Adventure didn't have enough really for a full go-go-go day, but now I think it does. Depending on our schedule, sometimes we get Park Hoppers now, sometimes we don't.
I agree with PPs that Downtown Disney is the easiest place outside of the parks to get food. It's very different than Florida - a wide variety of stores/restaurants, only a few Disney places. Short walk from either park (the entrance to both parks and Downtown Disney are all off of the same main area).
Weather in California in the summer - including September - is a crap shoot. It could be hot, hot, hot or it could be quite pleasant or even sort of cool, especially in the evenings. I've been at the end of August several times: once I needed to go out and buy long pants and a sweatshirt to wear out to the parks in the evening because I packed all wrong, another time I just wanted to live in the pool the whole time because it was miserably hot. November is generally OK, cooler but not seriously cold - although the rainy season starts about then so you might have to deal with that.