I agree with one of the posters above for the most part. from EH village - Dunemere lane which becomes Further lane, then south to connect to bluff road around amagansett. Instead of biting off the entire napeague stretch (which I find exceedingly booring) on MTK highway (freshly repaved as it is) I would cross north onto cranberry hole road to napeague meadow road (it might add a 1/2 mile to your mileage), riding through those marshes that were alluded to above. Connecting back to mtk highway, head east.

If you want wide shoulder and smooth pavement with highway speed traffic, with the big overlook, go new mtk highway. If you want smaller rollier hills, slower traffic, with a few ocean views on a tighter road, take old mtk highway. I actually switch it up when I ride out there so I like both, but I am usually doing an out and back.

Once you are in town, there is only one route to the point if thats where you are going.

You'll be happy you waited. After labor day would be the best time anyway.