It's in the lee of St. John and if you stay close to shore, inside Johnson Reef, it should be fairly calm.
It's a pretty long way 6-ish miles as the crow flies ... not really hike-able.
If I was going to make that trip in a dingy I'd bring a hand-held VHF radio, GPS, PFD's for everyone, and water.
A small center-console boat would be much better than a dingy for this trip.