Actuals
Riverdale into Southern Westchester, following Bronx River trailway after Bronxville
Route taken on Google Maps (kml) (Streetview works for part of the route, showing some of the Bronx River Parkway Trailway.)
With elevation information, which is too big for Google Maps but works with Earth (kml, kmz)
Summary Data: 23.7 miles, most of the day with stops
Planning
Rough google map route of lower (aborted) part of trip.
Nearby places on this route created with Google's My Maps: early and late.
Some useful links.
