We did it the first time we visited St. Marten--I can never figure out how to spell this island. The buses were comfortable, and the guide did a good job of explaining life on the island. There is a stop at a local outdoor market--like a flea market in the states.
Another option is just to take a taxi around the island a bit. We have also done this when cruising with another couple. We were fortunate to get a really nice driver. Get a quote before you go. I think ours was $40 for four of us. We thought it was well worth it, and we tipped him quite nicely.