I will give you my solutions A and B
All water into the RV went through a cheap home activated charcoal filter
I took some PVC pipe.. (I'd recommend 2" I used 3 and as a result did not have a pipe wrench that fit) and some reducers. The outlet end I cut a stainless steel drain cover to fit inside the largest reducer and glued it together (reduce down to male hose fitting) the other end a threaded adapter and then reducers to a female hose end. Cut down drain cover optional
Fill with Fliter floss.. (Fish isle at any store that has one) then regular not anti-algi) activated charcoal. then some more floss and assemble the female end.
Drinking water A: went through a BRITA pitcher B: When the Brita broke I replaced it with a PUR (the pitcher did not bounce well and PUR was what the Thrift I was voulenteering had in stock)
I still have the PUR and a PUR faucet filter as well