The only way to insure any level of reliability on a car this age is to rebuild all mechanical systems, and that can be expensive. Age is something very tough to overcome. If you want to increase your odds of enjoying your car start by replacing everything made of rubber. Hoses, belts and vacuum lines are the biggest reasons for the need for a tow truck, in my experience. However, if someone asks me where to start I always tell them to do the brakes first. I have great reasons for that.