With the one battery you have 50 amps usable to 50% state of charge. The refrigerator even on propane will need about 0.3 amps each hour when turned on to run the control panel and ignition. That may add up to 20 amps for the weekend alone. Using the water-pump, a light or two, can easily add up amps used.
I would suggest bring along a multi-meter to check voltage at the battery-terminals. You never mentioned the age of your battery, but it had better be reading 12.6 volts shortly after starting to camp (any reading over 12.7 volts is surface charge and will drop quickly after some battery usage).
The battery will read 12.42 volts @ 80% charge; 12.32 @70%; 12.20 @ 60%; 12.06 @ 50%; 11.90 @ 40%; 11.75 @ 30%; 11.58 @ 20%.
Your fan might cause the battery to read 0.1 to 0.2 volts low while running. Take a reading with it on. Turn it off and take another reading then. I would check your battery reading around 8:00 pm the first night to see where you stand. If you are not at least 12.50 volts (90%), your battery does not hold full capacity and you will have to cut back on usage.
If you do run the fan, check the battery voltage in the morning to see what your remaining battery capacity is. Base any future usage on the battery charge at that time.
