If you go into Street View in Google Earth (I just zoom in until it kicks me into street view, don't know if there's a better way to enter it) you get full WASD

If you go into Street View in Google Earth (I just zoom in until it kicks me into street view, don't know if there's a better way to enter it) you get full WASD control and it displays it on (pretty crude) geometry so the transition from frame to frame is continuous (and you can even deviate from the path in the street, though it gets more distorted the more you deviate from the actual car path).