The best way to explore St. Maarten/St. Martin is by car. Though often congested, especially around Philipsburg and Marigot, the roads are fairly good, though narrow and winding, with some planned speed bumps, unplanned potholes, and an occasional wandering goat herd. Few roads are marked with their names, but destination signs are good. Besides, the island is so small that it's hard to get really lost.
A scenic "loop" around the island can take just half a day, including plenty of stops. If you head up the east shoreline from Philipsburg, follow the signs to Dawn Beach and Oyster Pond. The road winds past soaring hills, turquoise waters, quaint West Indian houses, and wonderful views of St. Barths. As you cross over to the French side, the road leads to Grand Case, Marigot, and Sandy Ground. From Marigot, the flat island of Anguilla is visible. Completing the loop brings you past Cupecoy Beach, through Maho and Simpson Bay, where Saba looms in the horizon, and back over the mountain road into Philipsburg.