Assuming the soil won't be frozen when you get back, you would still be able to plant them. It's getting extremely late to do so, since the recommended time for dividing/replanting them is early fall so they can get their roots established. Getting them in the ground would be safer than trying to place them in cold storage. I would be sure and cover them with a light mulch to give some extra protection for the winter. As peonies don't like to be moved, you may have a 1 or 2 year wait til they bloom again. Also, be sure the crown (eyes) are not more than a couple inches below the surface of the soil.