Rivnuts from Homestead, PA on 10/8/2020 10:23:14 AM:
There is not a GAP trailhead at the Bowest Bridge itself in South Connellsville. There is street parking along 1st and 3rd Streets as the trail leaves Connellsville in route to that bridge. It is about a 1.5 mile ride/walk on the trail from there to the bridge.
Local residents may be aware of a closer place to park so watch for additional responses.