Well, I apparently over thought this! Really, this was extremely easy to do on one's own.
I had prebooked a historical tour for 1:45 pm. We docked on time and the ship was cleared at 11 am. We left the ship at about noon. We were docked at Pier 4 and it took us about ten to fifteen minutes to walk to Pier 2 (one of us is a slow walker). We just made the ferry that left before 12:30. The fare is $0.50/person but there are reduced or free fares for seniors depending on age. The ferry ride took only about ten minutes (including the time to tie up to the dock). It was a very short ride. As we exited the ferry terminal, there were white taxi vans waiting to take people to Casa Bacardi. For groups of 1 to 4 people, the taxi fare was $12. With five people or more, the fare was $3/person.
The taxi ride was fairly short and dropped us off a short distance away from the Welcome Centre. There we checked in. It was now about 12:50 pm. We were allowed to join the 1:15 tour since we were early and there was room available. We each received a pager to notify us when to meet for the tour and were given a token to get our free cocktail. We got our cocktail and had enough time to consume it before the tour started but some brought their drink on the tour.
We boarded a tram that drove us in a circle on the property and the guide pointed out some of the buildings and equipment used in process. A very short ride! The remainder of the tour took place in Visitor Centre where we watched a short film on the history, and then walked through staged displays of the distillation process and smelled the bases of the different rums they make. The final stop was at a "bar" in which the guide explained the different rums, three for cocktails and three sipping rums. As all tours tend to do, this one ended in the gift shop. The entire tour took 45 minutes from start to finish.
Afterward shopping a bit, we headed back to the taxi stand in the parking lot to wait for a taxi. I think we waited only about ten minutes for one to arrive. As there were only the two of us at the time, the driver suggested waiting for others to make the fare more economical. Five minutes later, two more people came along so it cost us each $3. He drove us back to the ferry terminal, and we got our ferry tickets. (BTW seniors who travel at a reduced or free rate still need a ticket.) We had to wait for the next ferry but it was not a long wait.
Upon our return in OSJ, we strolled along the waterfront, checking out the artisan stalls, making our way back to Pier 4. I believe we got back to the ship about 3 pm.
The tour was good but not great. Given that the cost was $15 and included a beverage priced at $8 if one was to purchase a drink there, the tour was really only $7. I think as long as one has reasonable expectations, one will be satisfied with the value of the tour. I would come back to Casa Bacardi but would do another tour next time.
For the two of us, our total cost, not including our shopping, was US$43.50 ($30 tour, $12 taxi and $1.50 ferry (I paid for the senior on the way over but not on the way back)). The cost of the ship tour was US$74.95/person (which also included a self guided visit of San Cristobal Fortress).