I live in Northern CA. Chain restaurants tend to have big portion sizes (I remember the Cheesecake Factory used to be unique with this concept 20 years ago, but that stopped being the case about 10+ years ago). Stand-alone restaurants, I think, usually have normal portion sizes. I used to be perfectly fine with having doggie bags but, in the interest of not spending more money than necessary eating out, DF and I agreed it's better if we share a single dish that we finish rather than spend the money on two dishes that ends up being too much food.
Menus -- chain restaurants typically have pretty big menus. I find the trendier sushi places tend to have huge selections of rolls.
Cuisines -- American steakhouses, burger joints, diner-types, Chinese, Japanese, Korean, Thai, Vietnamese, Laotian, Nepalese, Filipino, Indian, soul, bbq, vegan/vegetarian, Mexican, Spanish, Afghan, Russian, Ethiopian, French, Italian, Moroccan, Brazilian, Greek, chip shops/pub fare -- don't know if I'm missing anything else. Of these, I've yet to try Nepalese, Russian, Spanish, Brazilian, Greek and Moroccan in this area. Would like to say Basque (which I just tried a few months ago), but that was in Southern CA (well, maybe Central CA).
Most common cuisine? Not sure -- maybe Chinese.