ok...looks like I got an affordable lodging for us in downtown Charlotte Amalie....yeah! I want to see STJ iconic beaches so how far to the ferry spot to launch trip to STJ?-
You will taxi to Red Hook, on the other side of STT, (about $15 per person)then people ferry to STJ (about $10 one way per person). After reaching STJ you can take a taxi to beaches. I have no idea on taxi to beach cost - the taxis are open safari style. Most beaches do not have facilities, so do your research and bring what you’ll need, depending on where you plan to go.
There is a limited but closer to town passenger ferry - the Crown Bay ferry. Ferry schedules are here:
Taxi rates for St John here: