u/FieldsJ87

Have about a 20yr old sprinkler system and the valve boxes are buried, but their location is a mystery? Anyone have any tips on locating these other than walking the lawn with a metal detector and digging holes? The system has 6 zones and 2 of the valves and the main shutoff are located at one corner of the property near the street. Do you think renting a DPR will be my nest option?