All depends on your budget. If you can afford a separate battery, do it. For everything it will run about $500. If you can't afford that you'll have to live with one battery. Then you have to choose between an OPUS and an inverter. I went with the inverter because I have the need for more watts than the 150 that the opus provides. If your only running what you said, I think you would be fine with an OPUS. But if you ever want to install a Beer Fridge and a microwave for pizza, you'll be screwed. Can't plug that into your OPUS.