I took a quick 1.5 mile ride on the Jumpoff North Trail and took it to the point that it joins with the Shoreline Trail. It was early enough that I had to take a headlamp for the first portion of the journey, but by the time I hit the turn back point it was pretty light.
The north trail ends up joining up to the canal road, and a Shoreline juncture, and if you take the Shoreline portion south I believe there is another split off that continues to go up Jumpoff Canyon, but I heard it is a bit steep for biking and have not yet tried to prove that statement otherwise.
