LA -> San Fran

Hi...My friend and I are planning a trip to America from Australia in November and I would just like some thoughts on our itinery.
Neither of us will be able to drive so will be relying on buses and trains for the whole trip and we have around 25 days to sight see between LA and San Fran.
We are planning on basing ourselves in the big cities and then taking day trips/tours, I just do not know what it will be like getting around without a car?
We are flying into LA and plan to spend around 9-10 days there(is this too long?) before heading to San Diego and Tijuana for 4 days.
We are then going to head to Las Vegas for 3 days and take a tour to the Grand Canyon while we were there.
We have then got a couple of days without anything planned so if anyone has any ideas that would be great! We are then planning on heading to San Fran for 4-5 days.
We are very flexible with out plans. We will have just finished school so are after a relaxing trip with everything spaced out!
Any advice or thoughts would be greatly appreciated!!
Thankyou!

Welcome aboard the RoadTrip America Forums!

Both San Francisco and Los Angeles have extensive bus systems (Hint: look through their somewhat overloaded web sites for the system maps and schedules.) In addition, San Francisco has significant subway service, BART. Los Angeles also has limited subway service, covered on their general public transit web site (above). Get printouts of all these system maps before you come, but you should be able to get around in these cities alright. To get between them, I'd recommend the train (AMTRAK) so you can enjoy the scenery. Between L.A. and San Diego, Caltrans offers train service in addition to local commuter trains. Both of these services will afford you the opportunity to get off at some coastal towns like Oceanside for a day at the beach.

In Las Vegas, if your hotel is on The Strip, you can walk to most attractions and the main airport is a short cab ride away. I'd also recommend a flight over the Grand Canyon from Las Vegas rather than a bus tour, as the Canyon is far enough from the city that you'd spend most of your time driving too and from rather than enjoying the Canyon. Flights are a bit pricey, but the US dollar is low at the moment so the exchange rate should help.

AZBuck