I checked out google street view - from what I can see there's a sidewalk in the park, that may or may not be signed as a MUP (multi use path). Outside of the park there are no sidewalks or bike lanes in the area, unless they've been striped since the street views were made. In order to go across the bridge it is necessary that you use the street - the moment you decide to do that you are officially a vehicle, not a pedestrian, so the no ped crossing signs have no bearing on you as a cyclist - you are not disobeying the traffic laws. The best way to handle a situation like this one where he lanes are narrow is to simply take the middle of the lane- across the bridge no one has any business trying to share that lane with you, they can wait the few seconds it will take for you to cross safely. At the lights, the same - claim your space, use the lights the same as you would in a car. I can't see any other way unless you intend to ride in the grass...