still going to be on your back, dude. no free lunch or mass without weight.

if you have a physics book that will be in there..

the Burly Travoy is a good Idea.. lets you load a lower bag
with the heavy books, and a lighter load in an upper bag,
like lunch and clothes for changing weather.
bags available accessories to the trailer..

off the bike it is like a Fridge dolly, to wheel around.
to still not have to carry the stuff on your back.