Well, I would try to imagine the situation and what things you are likely to need and make your list.

For example in my case, the building I work in could be damaged in an earthquake. Getting out of the building could be an issue. Hence I decided to put gloves, a small titanium crowbar and an escape rope kit in my kit.

But everyone's situation is slightly different so you have to consider the specifics of your situation.

I also found it somewhat helpful to write just catagories of a kit (w/o the specifics) to help organize my thoughts. Something like this:

Personal Medications
First Aid
Food
Water
Environmental Protection
. weather / exposure
. [ heat, cold, water ]
. hazard [fire, debis]
Extracation
Communication / Signal
Mobility
Navigation
Information
. manuals
. frequencies
. inventory
. maps
. contact information
Utility
Comfort / Luxury
Spares / Duplicates
. [ eg, glasses, knife ]
Repairs
Defense
Special considerations
. [ eg, airplane travel ]
Other

You might keep a small pad with you as you are likely to think of things at random times. That way, you just whip out your pad, write down your thought and then go back to what you were doing.

I also found it useful to review other people's kits. I like to look at what people carry and think to myself if the various items would be useful to me. For example, Schwert has a kit very similar to mine (although a bit different approach). No big suprise since he is planning for the same types of problems. No big suprise since he works about a half mile or so south of where I do. :-)



One thing you might want to do is check some reviews. I didn't find much when I looked for reviews of the Cross Country II -- is it a new model? For example, look here. If you can't go see and try your pack, it mght be good to pick one that at least you can read reviews about. Considering you are talking about seven days worth of food and possibly water, you probably want to make sure it does well with heavy loads, esp. if you are thinking you are going to need to cover a lot of miles with it.

-john


Edited for clarity (hopefully).