West marine and other boating shops carry a myriad of electrical stuff. Fuse blocks, connectors, terminal blocks etc.
There is anti-oxidation compound that can be found at any place that sells electrical supplies, the brand names are Noalox and Penetrox. I suggest putting this stuff on ALL mechanical connections (screws or bolts) and EVERY connection that is outside of the passenger cabin. It is goopy shit and you can make quite a mess with it however it will preserve the integrity of the connection for many years. In the electrical industry we use it in high moisture environments and anywhere salt may find its way into the equation.
I have used the stuff on boats and in Marinas and never had a problem.
I feel it is one of those cheap insurance while you are in there type of deals.
Good Luck
Justin
PS I am doing a complete re-wire also and I am going to do my best to document everything.