Complete agree with th Val's recommendation. If you seriously want to check out CV: http://www.chowhound.com/topics/364354. Which says:
Castro Valley is less than enticing but there are some gems:
Burrito Loco on Redwood Road (Albertson's mall) for basic Mexican but with excellent salsas and tender chicken tacos.
Willow Park Paradiso on Redwood Road heading past Proctor Elementary School -- sister restaurant to Paradiso's in San Leandro (which has crashed and burned). While the SL location seems to be reeling, the Castro Valley restaurant keeps improving with a focus on beef and seafood.
Sunflower Cafe and Carree Outee on Castro Valley Blvd. -- both restaurants serve acceptable Chinese food of the mainstream variety. CO is a pick up and eat at home place. Sunflower has a tiny eating space.
Rudy's Donuts on CV Blvd. -- Castro Valley favorite; just good old fashioned donuts.
Molcajetes on Redwood Road near Trader Joes -- home style Mexican with homemade corn tortillas and pretty good Sopa Azteca.
Thai -- Castro Valley has recently become the home to three new Thai restaurants. I've only tried the one in Castro Valley Village, but the one on Castro Valley Blvd (Thai Hut) has received some good notice on YELP. I prefer Thai Garden in Hayward on Mission.
Speaking of Hayward: Neumanalis on B Street serves decent Cal-Med food; kinda pricey and service is spotty but worth a try.
Hope this helps,
Another vote for Thai Garden in Hayward (on Mission, almost to 238). Although we no longer live in the area, it's a regular stop when passing through. Val's does excellent burgers.
Not much to recommend in CV proper. Carry Outee has tasty food, but they won't prepare it without MSG. Avoid Fong's Dang How like the plague, unless you like flavorless gray 50's Chinese food.
For a quick lunch in Pleasanton -
Pho Hoa toward the very end of Santa Rita Road/Main street. In the mini mall on the right side. The place feels clean and impersonal - has those dark green mall restaurant chairs. A bigger space than Berkeley Pho Hoa.
It's not the best pho - slightly less satisfying than Oakland offerings, but actually not too bad. It is better than Berkeley Pho Hoa, and almost as good as Pho Hoa Lao on 10th street, Oakland downtown. It was completely packed when I was there.