A good thing for route planning is simply Google Maps. Instead of using driving directions, you can click on the bicycle symbol above the address bars and they will suggest bike routes for where you want to go. It's very easy to change the line of the route if you want to make any modifications too.
I just used it today for a nice 40-mile ride. My wife's friend was throwing a bbq and I decided to bike there 40 miles while my wife drove.
