Two obvious things from what you say: if you could reduce the family automobile population to one, you'd probably save a bundle. The other thing might be to re-think pruning your bicycles. Your kids might find them invaluable for getting around town, a lot better than getting part time jobs to pay for their own vehicles.

I too have had more than a few years when I thought the roof was going to collapse. It is important to realize what the real priorities are. If you can stop worrying about the things you can't change and save some mental energy for important events with your family. For example, you probably can't afford the an extensive summer vacation, but maybe you can substitute something just as much fun, like a camping trip to a local state park for a few days.