For me, I guess planning isn't an issue-I usually have a kitchen full of hiking type foods, so all I have to do is think "how many meals" and start bagging up. I can do a trip up in a couple minutes to a half hour. Then I note what I am missing and get cracking on it ;-)
Then again, I do dehydrate a lot, so I have bags of stuff to take from (pasta, mushrooms, beans, meat, etc). That speeds up life.