Doons:
Should be no problem. Just follow the channel from Stonington, around Sandy Point and carefully up Little Narragansett bay. I draw 6 and did it last week with no problems. just be careful to stay in the channel. The narrow passage between Sandy point and the green buoy is very narrow, but plenty deep. Do be careful of power boat wakes as they might bottom you out in a few spots if you try and pass at low tide.
Be careful to stay in the center of the channel, as possible, in the narrow pass before the turn at the entry to the Pawcatuck River. Bad rocks to the north and shallow buoy moorings on the south.
Anchor well at Napatree and be careful of dragging when the tide and wind shifts. There's a lot of kelp and some anchors don't reset well. Even if you hold others often do not.