Except for Los Angeles, there should be hundreds of places within walking distance in Las Vegas and San Francisco. The older part of Las Vegas, the Fremont area, has a lot of older casinos and they all have places to eat. In San Francisco, you probably can't go more then a block or so and find 3 or 4 places to eat. In China Town, look for small hole in the wall places with Chinese people eating there and you will probably have excellent food and reasonable prices.