The few gravel roads around here are accesable via a rail trail system. The rail trail head is 5 km from my house, but the road to it is great with a fairly wide bike lane on it so its no problem. But then the trail drops 600 feet before it clims again, the clim is 25 km long at a slight grade, 1 to 3 %. Any how, I can ride off road in one direction for about 120 km with very little paved sections, and the rail trail passes through a conservation area loaded with hilly trails.
As much fun as it is to blast along the paved streets here in the city, I do 90 percent of my riding down the rail trail and off in the woods.