For New Jersey, New Jersey Bike Map, now exclusively on FaceBook, is a great resource for building your own rides. Suggestions from others on general resources are the best way to find routes on a broader basis. When I lived in NJ, I could ride a different 40 mile route on relatively untrafficked roads every day from where we lived north of Princeton. Living in northern New Mexico now, roads are limited and generally dangerous. I stick to gravel and forest roads mostly here.