John, that's not a bad rate, but you may be able to do better if you watch sites like Breezenet, etc., closely between now and then. Most major rental companies at gateway airports offer a free shuttle to and from the rental site. If you stay on this over the coming weeks, I'm sure you can find a similarly good deal with one of the companies that will shuttle you comp. Reserve, find a better deal, cancel, re-reserve!
If you find an exceptionally good deal, be sure to verify that it's unlimited mileage. Some rental companies have been known to offer unbeatable rates, but the fine print doesn't offer free unlimited mileage, which most people expect to be standard nowdays. If you have any plans to leave CA with the car, be sure that the rental terms allow you to take the car into that state. From what I know of your trip, though, this doesn't sound likely.
One other thing - many rentals now come with built-in GPS tracking, whether or not it has a GPS system for driver use. Some rental companies have the GPS systems set up to alert them if the car exceeds X mph over Y period of time. I have a friend who was popped an additional $500 a couple of years ago when he turned his vehicle in (Avis, I believe). Basically, they cashed him out for speeding. When he objected, they pointed out the fine print in the contract which allowed them to do that. These GPS systems can also let the rental companies know if you take the vehicle off-road, which can be another surprising "excessive wear and tear" fee when you turn the car in.