Talking to people doing circumnavigations with autopilots, the great majority (70%?) have had significant problems. Redundancy is your friend, either two autopilots or autopilot and vane.
Heading back to Lake Ontario for this summer. Relatively few stops along the way from Grenada. Martinique, Guadeloupe, St. Martin (must have something to do with the French food), then Bermuda, New England and up the Hudson/Erie Canal. We were going to go via Newfoundland and Labrador but June remembered that one of the kids is getting married this summer - details, details!