"I live in Great Neck, so have done more or less this trip numerous times.
The choke point is crossing the Alley Pond / Cross Island Parkway area and as well every road going into Port is narrow and overloaded, but it is workable except during evening rush hours.
I usually take the 34th Avenue Bike lane to the end at 114th Street along the Grand Cental Parkway then south (right turn) to Roosevelt Avenue (turn left) and follow that all the way to Northern Boulevard.
Northern is busy, but for most of the way has good shoulders.
You can also tkae the 73rd Avenue Bike lane on eventually to the L.I.E. Service Road.
Figure out exactly where in Port you are going; there are 3 roads in. With the exeption of the last one, all have shoulders that might measure 6 inches wide:
Plandome Road takes you through Manhasset and along the shore to the west side of Port and into Manorhaven.
This is an uphill left turn off Northern and from the L.I.E., turn left onto Shelter Rock Road, take this to the end, turn left onto Northern then RIGHT to Plandome.
Searingtown Road (Port Washington Boulevard after Northern Boulevard) takes you into the center of the Port Washington peninsula. These are busy but doable left turns off eitehr Northern or the L.I.E. service road.
West Shore Road runs along the east side of Port and climbs into the old part of town. From Northern, you veer right at the Aston Martin dealership onto OLD Northern Boulevard into Roslyn and turn left at the bottom of the hill. From the L.I.E., turn left at Roslyn Road, take this to the end at the ""famous"" Roslyn clock Tower and turn left past the George Washington Manor wedding/catering factory. This becomes West Shore Road.


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