Here's an overview using a subway map.
The route generally followed the 1/9 subway route
(red line on this map).
In the pictures below, follow the yellow line down the maps -- mostly along Broadway, with a detour at 53 Street to Fifth Avenue, then down to Washington Square (West 4 Street) and back to Broadway for the rest of the trip
Manhattan's numbered streets are 20 to the mile
Manhattan is just over 12 miles from tip to tip
NOTE: the pictures along the way, keyed by numbers in yellow, are snapshots, not intended as great art!
ALSO NOTE: widen your browser so that the snapshots appear to the right of their respective maps