There is a wire run port and starboard under/behind a wooden trim board. When you turn on your sheer lights... that is it. THat is one solution. The other solution is to pull the floor boards and follow those runs.
Personally, I would stuck the battery in the forward V and not run 2/0 cable from the main house. That is the best use of your money, time, and resources. You will still have to feed the battery via a charger, but you can either put a dedicated charger forward for that or run a echo charger from your main charger in the Nav station. That is your choice.
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Are you talking about an anchor windlass fwd or an elec (halyard) winch on the cabintop?