Thanks!
Hommlet is approximently 315 miles southwest of Greyhawk City if you travel through the Gnarley Forest. I you elect to go around the forest it is about 80 miles north to Verbobonc and another 450 miles east before you reach Greyhawk City. Taking this route roads and tracks are pretty much accessible.
I make it approx 315 miles as the crow flies through the Gnarley Forest as well. A safer and probably quicker route as the previously poster suggested is to Verbobonc and then along the bank of the Velverdyva River past the city of Dyvers using the better roads in this area.