Re: Electrical upgrade
Welcome! You are dealing with two SEPARATE systems - 12 volt and 110 volt. Sounds like you need to tackle 1 at a time. Possible exception is getting a 12/110 volt fridge.
1. Buy Nigel Calder's book on electrical and boat maintenance. Its the Bible.
2.Get a good digital voltmeter!
110 volts is dangerous if you don't know what you are doing - especially in water. There should be a Hubbell type 110 connector to shore power running to a breaker panel. From there, you need breakers for outlets and anything wired directly to the panel such as the A/C and fridge. Good luck!