Oh heck yeah that sounds awesome, i hope his knees are ready for it! Might recommend some trek poles to him if that isn't already a given? I really wanna go on a bit of a longer trip to do some mountain backpacking out west but i definifely need to train up a bit more. I did a couple day hikes in Colorado a few years ago and the terrain and scenery are such a refreshing change from Appalachia.

About the the filter- nah no way haha, a couple of the trails i did last year had cisterns of drinking water at a few points and another one i was able to cache water in advance at a road crossing about ten miles in. I'll check out the sawyer and cnoc, thanks for the recommendation! Heavy metals from old ass mining operations are a big concern in the backcountry water sources here, I'll have to brush up again on what's out there but from what I remember Grayl had the only filters that made any promises about heavy metal filtration. Kinda inconvenient since they don't lend themselves to hooking up to a bladder but i guess that's just the price of living in the dang rust belt.