You'll only be gone for a little over three months, and you said it will be driven some in the meantime. So it'll be fine. Just do your regularly scheduled maintenance at the regular intervals.
If no one is going to start it up and drive it for you while you're gone, disconnect the battery terminals (you may need to recharge the battery when you get back).
It doesn't matter whether it is full of gas or low on gas, because you are not going to be gone long enough for the fuel to be affected. Fuel is good for at least 6 - 12 months (or longer) when it is in a sealed container (like a Contour fuel tank). Same with the oil, brake fluid, etc.
If you are going to store a car for a long time (more than 6 months), you need to consider adding fuel stabilizer, plugging orifices, putting the car up on jackstands, etc.
