Unless the sign says that the road/area is "Closed to Public Access" then it is open (exception: fire danger closure or active work area) for walk in, bicycle or horse travel. The "No Motorized Access" is just that, cannot drive a motorvehicle or ATV or motorcycle on that road/area.
If you park and walk in, just be sure you are parked far enough away from the gate/off to the side to not prevent it from being opened and vehicles to pass by and you will have no worries about getting towed.
There are maps availble for Weyerhauser at several different stores, for the Coweeman unit, you want the St Helen's Tree Farm map. If you are in the Longivew area, Bob's Sporting Goods has these and several other maps.
Good luck, hope this helps clear up any questions or concerns you had, good luck!!
