The amount of energy that one can draw at 120V is pretty limited in comparison to the cost of a typical weekend cabin rental. Still, it might be best to let the owner know ahead of time that you would like to be able to charge your EV. This could get them thinking about taking steps to better accommodate EV-owning guests. Further, the owner could be encouraged to attempt to join Tesla's Destination Charging program and get a free Wall Connector. If there are Time Of Use electric rates in effect at the property, then the owner could encourage guests to charge primarily when rates are lowest (typically late at night).