I have the opportunity to restore a 1965 Mustang Fastback. My dad drove it into our basement and parked it. And there it has sat for 20 plus years under a cover. Only thing that may have happened is if mice chewed some wires but I haven't taken a good look at it yet. Where do I begin? Drain the gas? Drain the oil? Just a tune up and go from there to see what else it may need. Or do I need to take more precautions before trying to start?