If you try to cross the Lehigh with a raft, I believe the only legal launch points are White Haven, Rockport, and Glen Onoko. If the rangers see you launch anyway else, you may have to explain yourself. If the dam is higher than 300cfs, you'll need a raft designed for whitewater use or the rangers will definitely be interested. In my experience, the rangers seem to prioritize people who seem like they might drown (non whitewater boat and >300cfs) first.
If I were trying to get to the left bank near the mouth of Bear Creek, I'd try to go down from Tank Hollow. I've never done it. I'd imagine it's steep, remote, and full of the usual dangers in this area. It should be very possible though.