Originally Posted by
lostarchitect
I use a saddlebag with a quick release for commuting. It takes 2 seconds to remove it, and it doesn't get in the way of anything. Carradice saddlebag + Carradice quick release bag mount. I attached an old camera bag strap to the saddlebag so I can carry it off the bike like a camera bag.
+1 The Bagman quick release support changed my life! Seriously, super quick and a Zimbale 18 liter bag holds a lot of stuff (as would a large Carradice).
OP - if you want to stick with the back pack you might try changing mirrors. The EVT Safe Zone mirror is articulated every 1/2 inch along its arm, you might be able to adjust it to a position to mostly see around your backpack.