We went down there (Grenada and the Grenadines for a turn on the Windjammer) in late May early June last year. Unfortunately, that is the time of year when winds become less certain. The trades are more reliable earlier in the year. Once tropical systems start to come through, like anywhere else in the Caribbean they can kill, shift wind to less useable directions or deliver squally conditions.
We stayed at La Sagesse on the SE windward coast (trades trend to come from the east). You could walk south down the bay and launch, ride out and around the reefs.
There is a huge sand beach along the SE coast around Gt. Bacolet fully exposed to the trades. Problem is, there is a massive, shallow (inches deep) rock reef just off the beach. The wind was light when I was there not sure how easy or safe it would be to get past that reef to get out to ride in normal trade winds.
We looped the island by car (renting is apparently not a great idea due to road hazards) and went through a bunch of the Grenadines. Have some ideas for possible launches throughout.