The Old Westbury, Brookville, Muttontown, Old Brookville
area has some nice quiet roads. I can't really recomend
any specific roads, those areas are full of rich folks and
those towns have their own Police forces, the kind of cops
who hate the very sight of me. So I only ride around there
on organized runs.
If you have the time, cross the Whitestone and head North. there are so many nice roads up here, you'll want to move upstate. Seriously, if you want a real nice ride in the spring, you should try Rte 22 North. I do it every year and it just gets better each time.
The key to good roads on Long Island is getting up very early on Sunday morning. I like Route 25 and 25a, Ocean Parkway, Whiskey Road in Rocky Point, and William Floyd Parkway. I actually find Southern State Parkway quite enjoyable at 6AM on Sunday, particularly the stretch between Wantagh and Cross Island Parkways.
Of course, getting off Long Island is the best idea of all!
2am on the Northern State is nice. Mostly empty.
I also like 25a east into Cuchogue and points east.
If you go through Port Jefferson make sure you stop at McNullties ice cream in Rocky Point(I think)
Monauk Hwy around Oakdale is pretty scenic
and be sure to cruise the residential areas in the Stony Brook/East Setaulket areas.
Join the group too