http://www.oregonstateparks.org/park_188.php
you can start in either cannonbeach or seaside. i prefer the south route from seaside.
the state park area is day use only. so no overnite parking. but there is lots of parking closeby. this area is full of history, if you take to that sorta thing. seaside is larger and more "commercial" than cannonbeach. both have large municipal "visitor" parking lots that are free and allow overnite parking.
there is also a shuttle between the two towns if you dont feel like hitching a ride
http://www.cannon-beach.net/shuttle/cbshuttle.html
with the 4 adirondaks in hikers camp, no need to bring a tent/hammock(unless ya want to of course). my niece and i each brought a pad and a wool blanket. which in early sept temps was just fine. since we went in the middle of the week, there was no one else there. tho there were numerous hikers along the trail to the lookout. theres no reserving an adirondak. just show up and use any of the four if no one else is using them. there is a communal firepit and large covered area with picnic table. also bundles of dry firewood for a $5 donation(theres a metal box for $). nice as tho there is quite a bit of fallen wood to be gathered, it can be very damp. there is no access to drinking water. this time of yr with the chilly nites and frequent rain, not likely there would be any "tourists". unless its really wet, expect frequent hikers from the day use area outside cannonbeach. its a popular trail up from indian beach. its less than a two mile hike mostly up from the nearest parking area. about 4ish into cannonbeach(take the trail not the service road-much more interesting). you will likely be awakened by the sea lions at the tillamook rock lighthouse. amazing how loud they are from that far away. lovely bit of cliffs and woods along the coast. a must do if yr in the area. lots of literature available about the history, flora and fauna if you like, at the visitors centers in both seaside and cannon beach. 1st time i did this trail we left from seaside and returned the same way. didnt go to cannon beach at all. would of done the same this trip, but my niece wanted a day in cannon beach. if you do go to cannon beach i highly recommend bills tavern. they make their own beer and have good, fresh food. some of the best clam chowder ive had. inexpensive too. enjoy!