The cheapest way is just run extension cord to the place where you want the power.
Next step would be running hardwire from inverter plug into additional wall duplex. New era duplex come with USB outlets as option, what solves several issues.
You mark the duplex "inverter" and all you have to do is remember that when you plug shore power.
The best is transfer switch, with converter rewired to shore power connectors.
Similar best option is buying converter/charger with transfer switch built in. That also will give you better converter, than TC manufacturers put into those units.