If you had some time to kill in Tortola and you wanted to stay close-ish to Hodges Creek Marina (MarineMax), what would you recommend doing?

We arrive on Tortola quite a bit earlier than the rest of our group and have pretty much the whole day to adventure out and have some fun. I was thinking that taking a cab to Josiah's Bay for the day might be the ticket... I don't want to stray too far away in order to keep cab fares somewhat reasonable.

Any input or other ideas?