We stayed at the Windjammer in March. It is a mile off the main highway so nothing is really walking distance from the resort. If you want to explore and take in the local cuisine rather than stay on site you need to do one of two things 1) rent a car (not many places to park at Windjammer) or 2) hire a cab driver. You will need a car to get groceries or dine out off site no matter where you go.
Rather than tacking the roads, we hired Norbert, who works at the Windjammer (ask for him, they will hook you up). Norbert was our personal driver for the week. Just tell him your plans and call when you need him. He took us on a trip down the west coast on our last day and it was great. He told us stories about the island and was a joy to be with.
We thought the on site restaurants were way overpriced and just OK for quality and rarely ate on site. The views at Windjammer are fantasic since it is built on the side of hill (mountain?). There is a good swimming beach onsite but we liked Reduit beach much better. The snorkeling in that area is not that good. The best place is the Sugar Beach resort, followed by Anse Chasenet and Ti Kaye. The Windjammer does have a watersports area with free kayaks, sailboats, paddleboats, snorkeling equipment, banana boat rides etc. I did not see any horseback riding at the resort.
Their beach is a cresent shape and normally protected from rough surf, but you get small wave action there depending on wind direction. Just beyond the breakwater, some locals like to surf in the 4-5 waves that are there. Some of the beach is roped off for natrual sea life, but the cleared swimming area is still large.