In Grenada now. Will be headed back north in about a month. Agree with rhans, would skip the St. Vincent circumnavigation.
And Seth's comments are spot on. Have been in Union several times. Never a problem. Always late may/early June. Couple of times in Frigate Bay where the recent attack took place (BTW, was at a South African wine tasting here in Grenada with Tina a week or so before the incident). Wife and I went ashore in Ashton and walked around as well in 2012. Never felt threatened in any way. "Stuff" can and has happened in most of the stops on your itinerary. Reciprocal courtesy and respect go a long way.
Have a great trip Dawg (if I may).