Inflatible backpackers' air matresses make a TOTAL difference in your enjoyment.
Camera like Flash1969 said.
Tarp may not be sufficient rain protection if you're in Oregon as your profile indicates. Carry sleeping bag in waterproof stuff bag, put waterproof rain fly on tent, plus use that tarp for ground cover under your tent. It can change from hot sunshine to hailstorm in about 10 minutes.
Campstove & fuel. Optimus works great.
clothesline like Fmr12B said, & a few clothesepins, to dry the damp sleeping bags & tent on in the sunny morning.
Tough plastic trowel for waste - disposal holes.
If you like wine, get wine in a box or collapsible pouch - no glass.
Good topo map, in a big clear plastic bag so you can read it in the rain.
Ask rangers if you need a wilderness permit where you're going. Ask rangers if any bearproof food lockers on the trail (is the best arrangement), or if you should suspend food supply on closeline between trees) old fashioned way, semi-successful).
Lightweight frisbee for something to do. Paperback book to read, Notepad to write journal notes & sketch on...you'll be inspired after all.
Sasquatch repellent.
Good sunglasses in crushproof case.
Before you go, study up on the geography & plants & animals of that area, so you know: emergency escape routes, plant & animal dangers. There's no help back in there.
Cell phone to call for help.
A small pair of pliers comes in handy often on backpack trips, & your knife.
Take only photos, leave only footprints.
