Hi MrMudstud,
That depends on what you want to run, and the time of year, so start with an energy audit.
If I avoid the use of my inverter and run my fridge on propane, I have more than enough to run my twelve volt side for probably 8 months of the year.
If you truly want to eliminate generator run time, the battery bank needs to be good for ten days total use. Some frugal RV's use about 50 amp-hours per day. That suggests a battery bank of 1000 amp-hours to keep above the 50% state of charge mark. To keep such a bank in good shape, solar wattage needs to between 600 and 1500 watts. Six hundred watts is quite possible but for 1500 watts there may not be enough "real estate" on the roof.
Costs for a 600 watt system run under $3.00 per watt for parts.