Put it under your console, along with the battery, make new cables if you have to. I like my switch to turn the WHOLE boat off, as its a trailer boat and the bilge pumps dont need to run like a boat that is in a slip or mooring.
I also like the ACR system, if you are running 2 battery's, here is an article and diagram on how to wire them.
http://www.jamestowndistributors.com...t.do?docId=170