We were down for the same week as the MIT group last year also. The Moorings handed us a sheet with the MIT itinerary and we avoided being in the same place on the same day. We ran into some stragglers at various points. All good fun-loving people but the anchorages on the list were crowded.

Back to the original question, May is a great time to go. We went later in the month (Traveled down on Memorial Day) and it was fantastic. All the places were open and it wasn't overly crowded. If you aim to get to most morning fields by 2:00 you should be fine.

Have a great trip!