I'm more accustomed to eating muesli soaked in fruit juice than eating muesli with milk. So take along some juice boxes and some paper or styrofoam cups. Pour the muesli in the cup and pour some juice over it, and let it sit for a few minutes. Take along some plastic spoons, and there you go.
I'd skip the Wonder bread (mostly because it is inedible to me) and pack flatbread - maybe like Swedish rye crisp type stuff. (Oops - I read what you said about rusks - maybe Swedish rye crisps are too similar to that!)
Consider taking some smoked salmon (I don't think this is the time to go for the cheapest options). How about some milk that has been treated with high temperatures and comes in packages (or just powdered milk?).
Nuts, seeds, dried fruits, and trail mix are a good idea. Go to the health food store and look for some types of combo bars that are much more appealing than the standard meal-replacement types. If it were me, I'd want some excellent-quality dark chocolate along - for quick bursts of energy. No need to eat much - just an emergency ration thing.
If I were in your situation, I'd consider writing out a complete list of meal plans for every day you are gone. You don't have to follow it, but at least you can see if your plans look tolerable overall.
[This message has been edited by WillTravel (edited 06-16-2003).]
[This message has been edited by WillTravel (edited 06-16-2003).]