Njr, have you looked at some of the female specific hydration packs or ultra packs advertised in the ultra running mags? They usually have a fairly accessible pocket, and you don't print as someone carrying. I run marathons, but won't start ultra or trail runs until I retire and can mile up properly. I know a couple of ladies who run their long runs in them and they have tried several until they found the one they like. They are light but I don't know how big the pocket would be. I also see folks running with lightweight canny packs too. Best, Bill S