This map shows the parking lot closest to the north pedestrian overpass (the little red pin marker). The north pedestrian overpass is our preferred site for bannering because it's close to a parking lot and a bathroom. The overpass is just to the left, or west, of the parking lot. If you want to walk, take North 59th Street east along the north perimeter of the zoo until you get to Aurora, then walk south on the unpaved trail on the zoo's east side along Aurora until you get to the pedestrian overpass. (Make sure to stay on the footpath -- don't get on the Aurora sidewalk or you'll be on the wrong side of the fence.)
If you want your phone to take you there, try inputting "Woodland Park Lawn Bowling Club" in your mapping app. The lawn bowling court is to the north of the bridge, but it'll get you close enough.