I always store my car during the winter in the garage. I always ensure that all the fluids or changed prior to the storage. As for the gas it is best to store the tank FULL with a fresh tank of gas. The reason behind this are:

1) Safety: the fumes in the tank are explosive, less air space = less fumes

2) Less air space = less corrosion possibilty.

3) More gas the longer it will take for it to break down.

These may not be the best reasons for storing a car with a full tank, but it make sense.

Just my 2 cents. Enjoy you trip

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1990 300CE-24
2003 SLK230 (Sport - 6spd)
1995 Ford Thunderbird