Edits: Initial questions were basically answered, new questions at the end of the thread.
So, I've done a few tours and am starting in on camping. Gear-wise I am mostly set, but have a few quick questions.
1) What is the best way to attach the tent to the rear rack? Edit: Answered, at the price of igniting a minor flame war.
2) Are stuff-sacks, especially the ones you get with the tent, usually water-proof enough for bike touring? (i.e. use them outside the panniers) Edit: Answered
3) If you plan to leave your bike & gear for a few hours (e.g. spend half a day hiking), what is the best way to secure the gear?
4) If I'm touring in somewhat populated areas and will not be stealth camping, is it a good idea to bring along some extra water (e.g. a 4-liter collapsible water container)? Edit: Answered