Your posting of your DR experiences sounds wonderful! We experienced similar in that we had a fantastic time. Half the fun was learning how to get around the place. One day, we were reading through the books that the hotel has in the rooms and discovered there was a shopping plaza just 5 minutes walk from our hotel. Nobody had told us about it.
Another day, we had hired a cab to go into town so we could just walk around the city. My husband speaks fluent Spanish so I felt totally at ease going into Puerto Plata with him. When we got to the central park near the cathedral, we ran into one of the maintenance fellows from our hotel. He moonlighted on his one day off a week from the resort as an information person in the park and he was amazingly helpful with finding us a place to have a cold drink, where we met a lovely Dominican family who I hope we will be able to see again next time we got back.
Our helper also introduced us to the guaguas and we were sardined into a minivan with 17 other people (your tale of 21 is amazing!) For 20 pesos we had a ride back to the entrance to the resort. The cabs would have cost 450 pesos. I think, though, that the guy riding the guagua "shotgun" so to speak wasn't too thrilled with the two of us gringos taking up so much space!

I could see him talking to the driver in Spanish and looking back at us. We soon found out that they were trying to figure out how to make more room with the two of us large gringos on board. We were asked to move to a two-seat area so he could squeeze five people into the four seat area we had been sitting in!
Here is a picture of our departing mode of transport. This picture doesn't do it any justice! LOL You have to experience it from INSIDE the guagua...the confined, non-air conditioned guagua!
We are definitely going back next year. It was the best vacation we have ever had, and we've had quite a lot of them. We have been to Hawaii, Florida, Georgia and this is the best ever...best place...best beach...best service...best value. We spent two wonderful weeks in Playa Dorada-Puerto Plata.
*sigh* I wanna go back NOW!
Vee