Hi Bob,
For Pro processing, Chrome is about the only game in town. There are a couple of other smaller players, but Chrome has been around the longest and has a good reputation. For film in 120 I would look into either George's or Nelson's, either should carry a full range of Kodak and Fuji films in 35, 120 and 4X5 (I'm a big fan of Nelson's not such a happy camper with George's).
As far as shooting locations for flowers and other greenery;
Quail Botanical Gardens
Balboa Park and the San Diego Zoo (they're right next to each other), Balboa Park has a gorgeous Botanical Garden, as well a Japanese Friendship Garden. The Botanical Building is 100% free, the Japanese Garden has a small entrance fee.
The Flower Fields in Carlsbad (may or may not be in bloom around the time of your arrival)
There are many other things to see and do as well. Tide pools in La Jolla and Point Loma (just below the Cabrillo National Monument). The Mount Palomar area (home the the world famous telescope) and Mount Laguna have some gorgeous scenery as well.
Feel free to PM me if you have any questions.
Cheers,
Andrew