Trans-pennine routes (Liverpool/leeds)

There's an actual transpennine cycle network.

http://www.transpenninetrail.org.uk/

Last time I did the Liverpool-Manchester section of that I had numb palms for days. That bit of the route is good for horses, who don't seem to mind huge potholes, but not much else. I think if you were going to try that a mountain bike would definitely required.