Great questions. We should collaborate on writing a user manual!
The water system has been a source of frustration. My first "fix" was when it wouldn't flow, and I found the vents for the two tanks went into a "T" which was behind the back panel in the port forward cabin hanging locker. They vent into the bilge. Mine had fallen down, creasing the vinyl tubing and preventing venting.
The two tanks lead to the the two ball valves under the galley sink. One must keep one only open at a time. My port tank has a gauge, the forward one doesn't. So, I run out the forward tank first, then switch to the port tank with the gauge. Sometimes the pump won't prime after I hit the empty tank, it becomes air-bound. I have to get into the port cockpit locker and loosen a fitting to allow the air out, and then it's fine. I bought an air bleed which I haven't installed yet.
I
did install a pressure gauge in the head to help with troubleshooting the water system.
I rebuilt the pressure pump. It wasn't hard, but the kit was expensive. I carry a spare belt for it. I have a new pressure switch which I haven't yet installed.
The plumbing is polybutylene with Parker O Ring/Grab Ring Tube Fittings. These fittings are great! My boat's plumbing had been butchered with an oddball collection of the original fittings, nylon, and brass, with silicone seal applied on the outside of leaking fittings! I took it all apart, and replaced it with the original style fittings and LLDPE tubing. The expansion tank was upside down so it couldn't be properly drained, and there was not ball valve to isolate it. Someone installed a fresh water washdown using nylon tubing and nylon barb fittings. Replaced and fixed it all. I have a lot of spare plumbing fittings on board. I bought them all from US Plastics, a fantastic business.
I don't have the forward cabin sink, I have hanging lockers port and starboard. My galley sink goes direct to a through-hull forward of the engine, next to the engine raw water through-hull. My head sink goes to a through hull under the head shower seat. This one, and several others, go to sea-chests. The main bilge pump is from the bilge near the mast to a pump under the aft cabin bunk. Under the floorboard by the main salon table is a tub that is the shower sump, with is pumped by a pump next to the bilge pump. The clear plastic things are strainers which need frequent cleaning. It's the same strainer as is used for the fresh water strainer under the galley sink.
I can go on....