ThermaRest or Foam Pad - unless you like sleeping on slabs, this will greatly aid in a good night's sleep. It also provides added insulation from the cold ground. Small Towel and Washcloth - at some point on the trip you will probably want to wash yourself. Campsuds or Biodegradable soap - optional. Toilet Paper - unless you like using your hand, washcloth or leaves, this is a definite must.
Most brands found in drug stores are worthless.
Its good stuff. When comparing repellent, look for amount of active ingredients on the back of the bottle, can or tube. Second Skin and Molefoam - a definite must for treating blisters. Imodium AD or other Anti Diarrhea Medication - its no fun having the runs in the woods. I recommend SPF 40 or more.