Public transit is probably best.

But you can buy a battery cut off switch, cheap and easy to install. The battery will last for many months if disconnected. Also keep the gas tank pretty full, and throw in a bottle of heet with each fill up. Modern cars have synthetic seals which probably won't dry out, so you can probably get away with not starting the motor for weeks on end.

If you wanted to go crazy, you could install a PLC to start the car and run it for 30 minutes each week.