But just to clarify, I do not want to go on this trip solely to view nature. It is also for the experience of being self-reliant (emotionally and physiologically), dealing with change, and isolating yourself from familiarity.
Other things being equal, it's more fun to do this in the midst of great scenery!
Just be careful--self-reliance requires skills that you need to master first. Otherwise you could end up like the "Into the Wild" guy--i.e., dead. You will certainly be challenged, no matter where you go, but you need to acquire coping skills, too.
On the pack, you want to acquire most or all of your other gear before buying it. Be sure to read the home page articles (previously linked to) on selecting a pack. Either take the rest of your gear with you to a good gear shop to select a pack, or, if you must order through the internet, once you receive the pack, load it up with the rest of your gear and the equivalent of 10-12 days' food and hike around the house or the neighborhood for a few hours. That way you can return the pack if it doesn't work for you. Pack fit is almost as individual as shoe fit--you want it to fit you and your gear!
IMHO, it's a good idea to keep your gear relatively light so you can carry 10-14 days' supply of food without the pack's being unduly heavy.