Book excerpt: In Backroads, New Jersey, Di Ionno leads readers off the congested interstates with their commonplace scenery to the seldom-explored secondary roads, where the real life of the state can be found. These inter-county or 500 series roads are a 6,788-mile network of mostly one-lane highways. Marked by blue-and-yellow five-sided shields bearing county names, they make up more than 20 percent of New Jersey's public roads. They are never the fastest or most direct way to get anywhere, but when you break out of the towns and hit the country, they are a pleasure to drive.