The week before Thanksgiving and the two weeks thereafter are usually the most reliable. Hoe soon that period begins seems to be dependent on water temps, however. People have good days prior to that, but I am speaking about reliability here.
As for flies, the primary forage fish at that time is the sea lance, commonly called sand eel. Google it to see a pic; that may be helpful. Bunker and mullet should be gone by then, but stripers are opportunistic predators, so fish-like patterns as well as eel-like patterns should be effective if stripers are in the area. For a fly angler without a boat or yak, finding spots where they are more likely to come close to shore on the right tide and right wind direction/force is key.
I also recommend that if you can, take a spinning rod. If the stripers are blitzing just out of fly range, you'll be kicking yourself. If you must have a fly, then even in that circumstance you can tie in a fly as a teaser above the lure.
