In general, all trailheads are day-use only with following exceptions:
You are welcome to park overnight at day use trailheads if going to be camping along the trail (at least 1 mile from the parking area)
If camping along the trail, you need to practice Treadlightly! (bury human waste, no campfires / stoves only, no clearing of vegetation...)
Mountain Bike Area #1 (Tillamook State Forest near Forest Grove)
Browns OHV Campground
Jordan Creek OHV Staging Area
Stagecoach Horse Camp
Nearest to trailhead is probably Gales Creek, Elk Creek, or (if you've got horses) Stagecoach
More info from ODF Forest Grove district recreation specialist: Stagecoach is for horses mainly. ODF does not encourage people to camp at trailheads due to parking and use constraints, but there is a dispersed site 1/2 mile further up road from Storey Burn that people are free to use.
$10 for Drive up sites and $5 for walk in sites.
Here's some rules scalped from ODF's site: http://arcweb.sos.state.or.us/rules/OARS_600/OAR_629/629_025.html On State Forest lands, no person shall: (a) Camp longer than 21 days out of any 35 day period, more than a total of 60 days during a calendar year, or the period of time permitted by the Forester; (b) Camp within 25 feet of any body of water or in other areas posted closed to camping by the Department; or (c) Leave personal property unattended longer than 4 days. Personal property left unattended longer than 4 days, without permission of the Forester, shall be removed by the Department and shall be disposed of in a manner consistent with procedures outlined in OAR 629-025-0080. (d) Leaving personal property unattended will be considered camping for the purposes of determining the length of stay at a given site.