Seems like Capitol Forest would be too close to Olympia if the intent is to break up the drive. But if you did want to go there, I'd go in at the Rock Candy Mtn. entrance off highway 8. If it were me I'd probably take the highway 6 route, and one spot would be just past the Pacific county/ Lewis county line. Turn right on Walville road and you'll only need to go about 1/4 mile and you'll be on state land.