Yes, I purchased the boat new in 2001 and I have certainly been through all the systems at least once!
The A/C Pump is mounted to the bulkhead, and there is only one. There is a TEE, coming out, to provide to both units. Getting to it, is a royal PITA. I changed mine a few years ago and ended up removing the aft wall of the cabinet. Made access much easier.
No easy way to clean forward A/C filter, other than lifting the mattress. I do it once yearly, so it's a good way to clean under there anyway.
The tank that you see through the mid salon hatch, is the waste tank. The pump which is mounted on a stringer is the fresh water pump. There is a filter attached, which requires cleaning every year. It is often a source of leaks!
The fresh water tank can be viewed via the floor hatch in the forward bedroom. You can view the fill line, and that's it. To gain access to the float switch and pickup tube, you will need to remove the bottom step, going up from the galley. There are hidden screws in the carpet.
Best of luck to you.
Gary