If you have enough space in the engine room and your wallet, you are better off getting a marine generator installed. If not, the 2k runs our A/C and microwave with no problem. A/C, microwave and hot water heater is not going to happen. There are power managemant issues, to contend with, but that is true of all smaller generators.
Do NOT buy the extended run kit. It is a $100 dollar option that can be put together for 40 bucks easy with parts from a hardware store. DO get an extra gas cap. You will need it for the extended run feature. That's only 12 dollars. You can also tap into the line from your tank to your engine and get all the running you want with no additional space taken up.