Hi Wayne,
Welcome to the PSA and welcome to the forum.
We too have a p-323 which also had mast step issues when we bought it. The OEM Pearson step was fabricated from mild steel which had rusted severly in the damp bilge. Even worse, galvanic corrosion between the steel and the aluminum mast had eaten into the mast enough to be of concern. This is a known problem with some Pearsons.
A few years ago, I took down the mast and completely rebuilt it, sandblasting it down to a bare pole and doing new paint, fittings, wiring, lights, and rigging. In the process of this, we had to cut off 4" from the foot of the mast and have a new step fabricated. I went with welded 1/2" aluminum plate on the theory that it would produce no galvanic corrosion with the alum. mast. Probably overkill, as the original steel step and mast lasted over 30 years!
As for the bilge, the shower and sink should NOT drain into it! I suspect a previous owner modified it. Ours has a small sump tank located under the large floor hatch in the main cabin. The shower, small sink, and the icebox drain into it. A manually activated electric pump empties it.
If you come to the July rendezvous we can compare notes. Looking forward to meeting you.