Here is a quick checklist, based mostly on what is
already in my pack.

Think light, forget nothing vital, take nothing extra.

Basic Core
 backpack
 sleeping pad
 ground cloth
 sleeping bag
 pillow ??
 trash bag to protect sleeping bag.

 (temperatures may well drop to 35 degrees, so plan to bring enough
 warm clothes to augment sleeping bag warmth).  Possible afternoon rain.

Clothing
 good shoes
 2 pairs good socks
 light shirt (avoid cotton)
 fleece sweater
 shorts (nylon or polyester)
 polyester thermal pants
 thin light shell pants
 warm vest (optional?).
 rain shell/outer layer
 warm hat
 gloves (optional?)

I have lots and lots of fleece layers that can be loaned, and shells too.

Personal gear
 water bottle
 sun hat
 sunglasses
 sunscreen
 lip sunscreen
 mosquito headnet
 hiking stick / ski pole
 cup and spoon
 paper and pen (for the journal writers).
 toothbrush, washrag, hygiene stuff.
 first aid (ibuprofen, band-aids, tape)
 flashlight or headlamp

Food - breakfast
  instant oatmeal
  rice cereal
  sugar
  tea bag
  gorp

Food - lunch
  gorp
  cliff bars
  granola bars
  ramen soup
  tortillas with peanut butter/honey

Food - dinners
  rice dinners
  couscous dinners
  more gorp

Shared gear
  stove and fuel
  tent, bivy bag
  cord/rope
  bear can
  maps

Optional Gear
  camera
  anvils, hardback novels, ...
  beware, every pound gets carried for 6 days and
  8 miles in (and 6000 feet up).