The Great Loop is the “Interstate;” the intersecting waterways are the “Blue Highways” — the rivers, lakes and canals that flow into the main stream. Ron and Eva Stob’s latest book, Great Loop Side Trips: 20 Cruising Adventures on Eastern North America’s Waterways, is the sequel to their highly acclaimed book, “Honey, Let’s Get a Boat…”: A Cruising Adventure of America’s Great Loop.