It's two days sailing time, Alan
What works for us is to leave after work and loading the boat, then anchor behind Charles Island the night before starting out. It sounds strange to go only a couple miles, but we get a nice early start the next day without feeling stressed.I would pay attention to the winds when picking a spot to anchor for comfort and safety, since you don't want to be forced ashore if your anchor drags.Anchorages I've used going East are:In the Thimbles in prevailing Southwesterlies.Tucked behind Sachem's Head in Southeasterlies and light Northerlies.Duck Island Roads in Southerlies, but watch your depth and consider the state of the tide, since there is some shoaling.The Clinton marinas make a good stopover in heavy Northeasters.There's a long shoaling reef oriented E/W. You'll want to go either N or S of it depending on weather and the state of the tide. If you arrive late, West Harbor on Fisher's Island is a good anchorage a couple hours from Mystic.Be prepared for some weird chop when passing the race.After Mystic, it's an easy sail to Block and/or Shelter Island/Greenport/Sag Harbor, all of which are worth a visit.E-mail me separately, rlzolczer@msn.com. I've got the NOAA current charts for LI Sound and we can make arrangements to meet and go over your trip in more detail.