1 - Change the oil and filter, the old oil has a high acid content that will etch things in the motor that is in contact with. That is the kind of thing that can cause you to have big problems down the road, like rod knocks.

2 - Disconnect the battery. Use a battery tender hooked up to it, this will maintain the battery for next season.

3 - Check the protection level of the coolant. Old 'green stuff' can go sour damaging the radiator. Newer coolant have the same effect - but a in a longer span.

4 - Placing the cars on jack stands keeps from getting flat spots in the tires. A good protectant to prevent tire dry rot.

5 - Drain the gas out and replace the in line fuel filter. If you disconnect the in line filter and hook it up to a rubber hose you can jump the fuel pump relay and use it to drain the gas out of the tank. Install the new fuel filter, hook up the fuel lines. Pre mix the fuel stabilizer and ONE gallon of gas, dump it into the tank. This will treat the left over fuel in the tank and keep it from varnishing up.

6 - Lock up the storage unit and go on your trip.

7 - When you return to start the cars, bring 2-5 gallon cans of PREMIUM, mixed with gum out injector cleaner, one for each car, dump it in the tank, check the air pressure in the tires, add air if needed, remove the jack stands. Install the batteries, disconnect the ignition system turn the motor over for about 20-30 seconds to get the oil back up into the motor-if the car has an oil pressure gauge, watch it and when it gets to around normal stop cranking and reconnect the ignition. Now when you hit the key there is oil on the critical parts of the motor and fuel to the injectors, flushing any old fuel out, and vroom it should fire right up.