I can't remember exactly where the Denny's is, but I think it's right about next door (if I've got the right address of 1700 Harbor Blvd - I google mapped it). If not, it's close and there's an IHOP right at the crosswalk that takes you into the plaza. I highly recommend IHOP over Captain Kidds (right next door) even though there is probably a price difference. Capt. Kidds has never impressed us (we stay next door to them at a Best Western). There's also a Tony Roma's right there where you are and a McDonald's further up the street past the crosswalk light.
Edited: I just followed a link that w-steele put on another post:
Bret's Disneyland Lodging LinkMap You'll see that you are right below Disney Way. All of the restaurants are in a smaller red font.