Do a, say, four-day, three-night shakedown tour now, a loop from home to home, equipped as you describe. I'm certain that it will convince you to abandon the backpack idea.

(Where does this backpack idea keep comiing from? Is it Camelback propaganda? Put stuff on your bike, not your back. Sheesh, Physics 101, Comfort 101. Backpacks were disproven on bikeforums.net by our youthful grandfathers back in the 1930s, and all the major world newspapers picked it up and published it just before all the heroic backpackless bike tours that preceded World War II. Read your history!)