Nate Harrison Grade
This is a popular route for mountain bikers and off-roading vehicles to go up to Palomar Mountain, but you can also run it! I parked where the AllTrails map took me, just where the road turns into gravel/dirt. I parked on the side of the road there and started a little after 9am. This route is about 8.5 miles uphill and then you turn around and go 8.5 miles downhill. I did not see anyone on my way up, but had some motorbikers and cars pass me on the way down. It was a long and tough climb up, I am glad I did not start super late, it would've gotten pretty hot.