I'm still gathering information and parts when I can find them.
Does anyone reproduce fresh water storage tank the will fit in the over the sink in the early Shasta's or something that has a tap and exits this hole?
Disreguard all the turtle stickers but I just you can figure out why we call the Shasta "The Turtle".... Danny
Based on what I have seen from your other builds, I know this trailer will not be a quick "lipstick restoration". You build nice "well engineered" vehicles without any short cuts, IMO.
So why stay with a gravity feed water tank? It was only done on a Shasta to save money, and allow them to advertise it as having a minimal water system while advertising a low MSRP. Since your replacing the tank anyway, why not place it under the front seat? Moving the 100 pounds low on the trailer would be a great towing stability improvement compared to high up in the cabinet. Any water leaks, or water spills while filling are better to have under a seat and not high up on a wall.
SureFlo makes a nice "on demand" water pump. If you use back flow valves you can use the same water lines for your city water system. I like to use PEX Sharkbite fittings and hoses with the copper crush fittings. I use white PEX for pressure lines. Blue PEX for suction (hand pump) lines, and Real 3/8" Copper for the lines from the water heater to the hot side of the sink faucet.
John's idea of an on demand pump and tank in the dinette is excellent.
That being said, I like the idea of keeping the original gravity tank, just for the cool factor. Off grid and all... I believe you can get a poly tank made in any dimension. Heat spun fittings are done by the buyer in any position, so easy to customize.