How much should I charge someone to plug an RV in at my house?

The heat in the RV is being run by propane. So I would say the only power needed would be to run the refrigerator. Although I don't know how RV's work. I would ume like most devices there may be some amount of draw even when the devices in the RV are not in use. The RV will be left unoccupied during the week and used during the weekend for about a month. It is 24 feet long and has a microwave, tv and stove. I live in NY, not the city, up with the cows.