Someone gave me this advice and I liked it, so I’ve been passing it along. Use the built in tank for rinsing and emergency drinking water only. It’s hard to judge the tank cleanliness from the outside, no matter how often you clean it or if you filter the water. We use our built in tank for dishes, showers, flushing, sometimes rinsing after teeth brushing. We carry a separate tank with filtered drinking water. If you have a trailer you leave parked, your drinking water is now mobile, it’s easier to fill up, clean, inspect and replace if needed. Scepter makes some smaller, 2.5 gallon tanks or buy a cheapo blue 6 gallon Walmart tank.
btw, nice build, just read through it and your buying process, lol. Been looking at replacing my GX460 with an HD truck for exploring and home projects and it was interesting to read through your process. I don’t think I have as much need for hauling and towing, so a PW is currently in the lead. I’ve made the rounds with sleeping arrangements as well with our two boys, from a tent, to a Lance truck camper, to now an off-road square drop camper with an RTT. Our square drop camper is by far my wife’s favorite and I think it hits most of our needs out of all the iterations we went through (no solution will ever be perfect). Biggest issue is that the GX460 is a complete dog at towing, even at ~3k lbs.