Kellogg's variety packs of cereals are all the serious survalist needs.
Yep - you're compelled to eat 5 days worth at a time, it's current survivalist-theory I'm certain
Regarding food best energy vs weight there is only one; Real Field Meal (NATO prooven) http://www.drytech.no/drytechen/index.php?option=com_content&view=category&layout=blog&id=70&Itemid=53&preset=orange
. The best thing about Real vs the standard old Military rations is that Real realy taste good and give you lots of energy. Real have been prooven in military services around the world, climbing expeditions, trans arctic and trans antarctic expeditions etc. Most other products (commercial branded) dont give you enough energy in relation to weight and mass. You might feel full, its like base you rations on rice and bread... not good! The Real Field Meal rations gives you 1400cal per ration. And if you put in 1dl grape oil in every meal and every thing you drink the effect of the calories increase. I tried this out on a three week winter climbing exspedittion. The average temperature was -25 degrees for the whole trip. After three weeks of skiing and ice climbing all participants had gained 3-5 kg during the trip!
Did almost the same trip 16 years ago, lots has improved in gear and food since, good luck and enjoy your fantastic country!
ps, do you include the Rallarvegen (Flam to Haugostal part) and the very scenic pass from Laerdal to Aurland?