If you are going to do your own rewiring, may I suggest the following: Always use marine grade stranded wire, usually tinned but untinned is OK too. I like to use adhesive lined heat shrink connectors for areas that may have moisture present (like bilges). Get a good crimping tool. Ancor makes em. (there are two different models of the tool, one for non insulated connectors and a different model for insulated. You would most likely use insulated connectors)
The Ancor hand held ratchet crimping tool works for 10 Gauge and smaller wire. For heavier gauge wires like I suspect your accessory feed might be, a different tool is needed and those can get costly. I suppose you might be able to use a non insulated connected with a sleeve of shrink tubing and a vise grip to crunch the connector. If you are going to make up battery cables and only have a few, buy them pre-made. Otherwise you will need a hydraulic crimper with assorted dies.
Don't forget to secure cables and keep things neat.