I have no idea how the Valencia would act on an awful road, although some of the roads I take aren't paved all that well. It's really meant as a commuter bike, which sort of implies decent roads. A very steep road also works against a hub motor I think, because they don't develop as much torque as a chain linked motor.

I'd start a new post asking what kind of ebike to use on a steep and bumpy dirt road. I'd bet that the Treks won't be recommended.