To The Sound (13.5 miles)

You can get an interactive map at the above link.

We’ve done this as a straight-shot to Larchmont. Once you cross Route 1, there are streets hither and yon, but keep moving east and you’ll hit the Sound. The Larchmont part is flat, but there are a few hills in the New Rochelle/Mamaroneck stretch (you enter Larchmont when you cross the tracks).