Couple tvs and a fan? Smaller is better IMO so maybe 300 watts. If you have space near the fuse/breaker panel you can use the main 12v feed for power and connect to the branch circuits you want with a transfer switch. This avoids pulling wire and getting monster cables etc. Just make connections.
I have a 300 watt GoPower sine wave inverter set up like this and it works beautifully. Has a provision for remote switch so with the push of a button instant power.
Any much larger you will need to mount inverter near the batteries and pull wire to the panel to wire it in.