Always connect Walking Trails. They can be routable (considered for routing), Waze will stop routing at the start of the WT, where the Wazer should ideally park and finish on foot. Connecting can be done using a phantom node.
Notice that this road type should only be applied when there are houses or other destinations along the segment (house numbers). Also non-drivable segments necessary to reach a segment with destinations should be made Walking trail to get an uninterupted route from the drivable road to the destinations.
For leading users to and from a parking lot place, Pedestrian Boardwalks were used. Because of a bug this isn't working anymore: you should use now Walking Trails.