Protective sleeve for camera+body in a backpack

I shoot most of my photos outdoors, often while on day hikes and runs with my Salukis. I need a way to protect my K-30 and zoom lens in my ultralight daypack when I'm not carrying it, and would love to hear how others deal with this. My approach to equipment is  casual and minimalist, so I am not looking for a  (heavy) photo backpack or camera case; I usually carry more gear, food etc. than photo equipment.
So far the best looking case or enclosure is the Crumpler Haven Camera Pouch Small -"fits a DSLR twin lens kit and flash". I'm curious if anyone has used this piece of kit or similar, advantages and disadvantages. Quick acces is less of a priority to me than protection and flexibility, e.g. being able to use the pouch in different packs with a couple of different lenses attached to the body.  I have an 18-55mm now, and plan to get a 55-300 soon.  Thanks