Himeji is a city located in Hyōgo Prefecture in the Kansai region of Japan.
To East or West
As often in Japan you need to go to the S.A or P.A, this time it's a big Service Area (top SA for East, bottom SA for West).
So use the train to go to Tatsuno Station (320 ¥ from Himeji Station) when you are arrive you need to go in North West to this Service Area (2.2km, 30min). You can cross campaign with dirt way, don't be shy.