[K2 Camper]

I want to make the outlet in my basement storage work off the inverter. We have a fridge/freezer on a tray in the basement storage and I want the outlet in there to work while we are on the road. Where would I find the bus bar or circuits that are currently running off the inverter? Can I double up one of those circuits or do I have to move a current inverted outlet to the source that feeds the outlet in the basement when I move the basement outlet to the inverter ? Thanks for any guidance. K2