To answer your question directly, REI sells several brands of freeze dried or dehydrated foods. They are all pretty much equal. Don't expect anything better than you would get at your average hometown buffet, which is to say they are not that great.....but livable.
I can enjoy the "mountain house" stroganoff, cheesy mac, kung pow, potato/onion/beef, chicken and rice, sweet and sour pork...most others I have tried are OK (like the italian dishes) and some are just plain wrong (like the breakfasts)
I have found I can live quite comfortably for long periods of time on my particular menu and that is all that counts.
I prefer to eat 3 fairly light meals, then gorge myself throughout the day on snacks. Longer trips are tougher to plan out, because food is heavy!
Breakfast--instant oatmeal/cream of wheat, power bars, instant pankcakes, coffee, cereal with powdered milk
Lunch--centered around ritz crackers with cheese, salami, pepporoni, peanut butter, single serving packets of tuna or chicken salad. I bring 1/2 sleeve of ritz crackers per lunch. I like to do a no cook lunch.
Dinner--I go with a couple prepackaged freeze dried meals like "mountain house" brand, but I will also do instant mashed potatos, shells n' cheese, soups....browse your grocery store, or places like Trader Joes and World Market for anything "instant". There is all kinds of stuff avaliable now that just needs hot water. Found some teriaki bowls the other day that looked good.
Snacks: Nuts, dried fruits, pretzles, candy, chocolate, any snack your heart desires. They are usually light and packed with calories.
The lightest approach would be all freeze dried, but bleahhh
Beware anything rich. You do not want to eat super rich foods (at least I don't) for days on end. While I love salami, I do not love to eat it daily....it is just too rich. So when choosing foods, remember a little variety.
I ALWAYS throw in some extra oatmeal packets and extra ramen noodles. They are cheap/light enough that I don't mind carrying them around. Delays happen. Sometimes I am extra hungry. I have eaten my spare rations on a few occasions.
I always repackage foods into ziplock bags. You can drop some weight and bulk quite easily there, and that always equals more food to squeeze in for the trip. I am a skinny guy because I burn fuel like nobody's business, so I need all I can get. You will thank yourself for the snickers bars and almonds you shoved into every nook and crannie.