The Rhode River is certainly not off the beaten track--on any nice weekend expect about 30 boats overnight and 2-3 times that during the day. But head behind Big Island, into the tributary and wetlands monitored by the Smithsonian Institute, and suddenly you are a different place. The occasional water skier or PWC may zip by, but mostly they stay out in the main course, where their friends can see them... I guess. On a weekday generally you will see no one at all. In cooler weather, solitude is certain, just a fraction of a mile from some of the busiest sailing waters on earth. Weird.
You can paddle up to the visitors center, about a mile up the creek, by passing through the narrow opening in the fish-counting dam, a ramshackle breast of wood and plastic mesh, with a now-dysfunctional gate wide enough to pass a kayak and fish, of course.
If your boat is shallow draft, anything less than 4 feet, you can anchor behind the island in about 6 feet of water. The holding ground is variable and not always as good as north of the island, but it is well protected and there is little drag into.