Groups like the Adventure Cycling Association (ACA) have currently mapped more than 40,000 miles of bike routes around the US. While they continue to work to develop more bike routes across the US, you can request a catalogue of bike maps to get you started.
You can help the ACA, and other groups like the National Center for Safe Routes to School develop a safe bicycling route in your area.
Or, in the case of professional cyclists Danny MacAskill, you can make your own route (do not try this at home!).