Promatory is a good spot, there are also little like 5 10 minute wheelin areas just little areas to go f*** around for a couple minutes. 185th between marine drive and sandy blvd., and off of US 26 E there is a street called Palmquest, right across form Superior Offroad, PM me and i can give you more details.
Sorry for the long Post but here it is Please read!
From my past experience Promatory is closed to anything but street legal vehicles that stay on the gravel roads. It was a 100 dollar lesson for me a few years ago. Had there been signs ect I would have never unloaded my Dirt bike there. As far as I know it is still that way.
My club Pistons wild has been working with Government officials in SW Washington for over 2 years now trying to get "legal" trails opened up in the
Yacolt Burn area that is north of Camas and east of Vancouver. This area is also known as 4 corners, jones creek ect. If you know of anyone that goes up in that area to "wheel" please tell them to stay on only the the gravel roads and not to go "wheeling" at all up there until we can get trails opened for the general public to enjoy. We are in the process of getting this in ink and we need all your help to stay out of all closed area's for wheeling. Get a hold of myself or post on our forum and we will provide you with legal spots to wheel along with maps ect.
Bad behavior hurts us all. I understand the frustration that we all have alot of money in our rigs and want to use them as much as possible. We have all been wheeling in places that we may or may not have known that were not "legal" areas to be, myself included when I was younger.
Please visit our website at www.Pistonswild.com
for more information on the Yacolt Burn project we have been working on for over 2 years now. We have over 2500 volunteer hours in this so far and we want to build something similar to browns camp within a short driving distance from Portland/Vancouver areas.
We also have a forum at our website with updates and info for all the projects our club does ect. Go check it out and we are always looking for more people to help us out. More hands make the work go easier and faster.
Thank you for your help and cooperation