Many diseases and conditions are spread by not washing hands with soap and clean, running water. If clean, running water is not accessible, as is common in many parts of the world, use soap and available water.
Riverdale covers about three square miles in area. It has one of the highest elevations in New York City, affording it views of the Empire State Building, George Washington Bridge, Hudson River and New Jersey Palisades.
As for Riverdale's location, that's a difficult one to pin down. In a 1942 issue of Jackpot Comics, the Archie crew were shown visiting Bear Mountain in New York on a trip, but that's no guarantee their hometown is located on the East Coast.