My Platys have held up for year, plus a patch kit is available.

That said, for a 6 YO, I'd probably go with disposable water bottles attached to the pack's shoulder straps. You COULD drill a couple of holes, one really small to hold a valve, the other for a drinking tube that reaches the bottom of container. Actually, some water bottles are made this way, so you could attach a bag to hold it to one shoulder strap.

IF your 6 YO can use and prefers a hydration tube/system, that can work, but I took a 16 YO out who kept chewing my spare bite valve, rather than holding it open and sucking. Until I know how a kid adapts to new things, I'm sticking to basics.

CamperMom