I personally would not use a moped or bicycle in St John. The roads are very narrow, no shoulders, winding, and can be steep. When vacationing there, we rent a jeep. The maximum speed limit anywhere on the island is 20mph. For our upcoming cruise, we'll just rely on open-air taxis since it is just a port day (and the two of us can do taxis cheaper). We're planning on revisiting our wedding beach (have ordered another small wedding cake from the same chef) and will do some hiking to non-touristy beaches before returning to the ship in Charlotte Amalie.