Re: While engine is out....
What he said. Paint the oil pan, especially if there is even a tiny bit of rust anywhere on it. I'm kind of a fan of Rustoleum or XO-Rust brush paint. If the pan is scary looking, replace it before it fails. If any of the hoses, particularly ones that are difficult to access need replacing, do that now. The one at the top of the drive that runs under the engine and comes up at the thermostat housing is kind of a pain to get at normally.
When I had my motor out, I did a lot of cleaning in the bilge. I also took the time to replace all the battery ends since they were in not so great condition, and replaced the bilge pump and the generator's water feed and seacock. I also replaced one of my battery trays (it was two pieces of plywood that had rotted), re-mounted the battery boxes in a more secure manner, and just did a general tidying of the wiring with some zip ties. I also put a new raw pump on my other engine, but you won't have that.