planning your own route

[jaker]

Are there any sat nav systems out there where you can plan your own route: i.e: I want to take the b3223 and then the a347 and then the b112 etc etc... such that the sat nav just acts as an advanced form of self-pre-determined directions. hope that makes sense... I.e: you fully decide your own route, the sat nav just tells you when to turn...

ta.