If you need basic information, start by googling "the 12 volt side of life".
You want about 100 watts of solar for every average sized RV battery. If that is not enough to meet your need, then you will need to add batteries as well as additional solar power.
The 12 volt side of life pages will give you information on expected electrical consumption and will help you size your system. LED lights, water pump and fans typically use minimal power. The big draws are the furnace and TV. A TV can pull 10 amps and drain half of your available battery power in one evening.