Man, I love these things.
I'm carrying 22 lbs. of fresh fruit from Haymarket, in this picture.
I carried that amount of produce in shopping bags, tied and hung pannier style around my neck, once. Use panniers.
Step 1: Prime the Jugs
Cut the tops off of two five gallon jugs, with anything sharp. A Bandsaw is the fastest, but a knife or a hacksaw work too.