From all the pics I have seen of guys using the longbow as a multi-day trip bag, they put the meat in between the frame and the bag. If you search on line there are a ton of pics of Kurt and Seacat doing it this way.
A back pouch from Kifaru in the back of the Longbow works well. If you put 2 rip zips (one on each side) and the back pouch on the back, you may not need the dry sack at all.