What's the best road to take to get from Fairview to NYC?

The most direct road is Route 9, but that's not the best (unless you want to hit dozens upon dozens of traffic lights). The best course of action would probably be to head down to Route 55 and go east until the Taconic Parkway. From there, you could either stay on that or hop on Interstate 84 then 684. Would not recommend Route 9 at all if you want to get there in a reasonable amount of time.