Oarai Station is only a railway station in Oarai-machi. Because this is the only station it is most likely going to be your starting point for your GuP tour.
There is a tourist information office in the station building. You can get a map of GuP in the tourist office. And, there is display of GuP. It takes 15 minutes by train to get to Oarai Station from JR Mito Station. Parts of the Kashima coastal railway trains have GuP decals.