The Sarasota/Manatee Bike Route Project is an embedded Google Map with a dozen suggested local loops. This idea is in the development stage.
The City of Venice Bike Map includes a marked 11.5 mile Island Loop. Follow the Red/Black arrows painted on the VWP and the streets.
The Legacy Trail/VWP offers 20 miles motor vehicle free bike trails.
The Myakka Island Trail is a 25+ mile long off-road bike friendly trail from the Carlton Reserve to the north entrance of the Myakka River State Park. Don't forget to plan on turning around and riding back or plan on having somebody pick you up. Be prepared there are no Tiki Bars on this route. You are on your own.
Maps for the Friends of the Lagacy Trail annual "Tour de Parks" event. The maps and Cue Sheets are from the 2013 event.
The Carlton Reserve at the east end of Border Road has over 100 miles of gravel, grass and dirt trails and roads that are suitable for off road, cyclocross and any bike with wider tires.
The North Port Connector Loop is a 32.5 mile loop thru the Carlton Reserve to Myakkahatchee Creek and North Port city streets and returning via Warm Mineral Springs and Deer Prairie Creek. The start and finish for this loop is at the public parking area of the Carlton Reserve. This is a mixed surface loop. An off-road capable bike with moderately wide tires (1 1/4', 32 mm or wider) is suggested.