Clark-Park is one of the suggested routes on the Trans-Alt Nassau County Bicycle Map. It's also the route used by the Montauk Century, Ride to Montauk Century and Ancient Mariner (to Montauk) and as such is part of the network of light traffic on-street routes in Nassau.
Here's a link:
http://www.transalt.org/files/resources/mapnassau.html
As such, it's more direct and significantly less convoluted though I wouldn't use the term "fast" as that's up to the rider. It does give up 1.6 miles of path, but is a pleasant ride none the less and I see ton's of riders on this stretch, weekend mornings.
SB