i generally carry a bumbag pete blands one with compression straps (cuts out the bouncing) or a back pack in winter conditions.
dont tend to carry water unless its tropical just drink from streams less to carry, if i do take a bottle i take a 1/2 litre platipus or running handheld bottle and put the bumbag strap through the grip hole.
but i prefer to travel lite with a bumbag water proofs, hat, gloves,map, compass,food/gels,(bivvey bag, buff, sometimes)