There are cabs readily available at BW at night. The cab ride will cost you about $12 and take about 10 minutes. The bus ride to DD and then to PO will cost you nothing but take anywhere from 50 minutes to 1 1/2 hours depending on waits. If MGM is still open when you leave BW, you also have the option of walking over or taking a boat to there and then bus to PO; that would cut about 15 minutes off the bus trip.