I grew up in that area, and while I haven't road Bear Mountain in 15 years or so, it is a great ride. Beautiful scenery, like another poster said, steady climb where you can find a rhythm, and just a blast. And I agree, definately have to go to the top, worth the trip.
And in the fall, with the foliage, it get's even better, an absolutely beautiful ride (be careful not to ride on a Saturday with an Army home football game though). Enjoy.