I have done the trip many times.
The key considerations are... the weather
and the tides!
If you are starting in NYC
... and are headed to LIS then you will HAVE to have the current
with you passing Hell's Gate.
Once you're in the Sound, since you will be spending some time at anchor
or at marina you can choose which coast to make home for the evening. Close in either shore offers good choices, as you get out east the pickin become slim on the Long Island
Since you'll be sailing all day or most of it, try to use the current
to your advantage. If the winds are from the south quadrants the LI shore overs some lee and smaller waves and you can stay out of the commercial
traffic which goes down the center of the Sound.
The ocean part (south of LI offers no places to duck in so be prepared to do the emtire 100+ miles without stopping.
Places to stop on the LIS route
of interest are:
Manhasset Bay (Port Washington)
South Norwalk (SoNo islands)
plus many more
CT shore is rocky and the achorages are more exposed to the SW.
You have two choice way out east - Plum Gut or the Race
at Fisher's Island or one of the passes between them. You need to pass them with a fair or slack tide and a decent motor
helps. From the race
it probably a beat to Montauk so consider the Gut and the options there.
You can anchor
in Gardiner's Bay by the Dutch Windmill at Gardiners Island and them work your way south through the buoyed channel along the north shore of the South Fork right out to Montauk Harbor.