If you have a list to work from and all your gear stored in a central spot, you should be able to 'bug out' in the time it takes to assemble your food + approx 1/2 hour. No need to keep it all in your pack. Especially since seasonal weather doesn't stay still, and whatever you stored in the pack might not be exactly right for the overnighter or two-nighter you want to 'bug out' for.