Since it doesn't look like you can get away forever without knowing where the valves are, you might as well resign yourself to the necessity of locating them.
I definitely agree but I don't know how to go about locating them without the use of specialized equipment. When I called the company yesterday that blew my lines out and insisted the zone be repaired before the winter, they said I had nothing to worry about and that in the spring they would bring a wire tracer which they would have to rent. Their primary focus is on blowouts now and they can't fit such a job in their schedule. Furthermore since this zone appears to have a low point (the sprinkler head on the back corner of my property) that I would be okay. I don't understand how they came to that conclusion. Either way they said if anything got damaged from freezing, they would be held accountable. I'm still not getting a warm fuzzy from this explanation.