sdr’s suggetion is a good way to handle it too.
About the plumbing and electrical. Circuits are designed below capacity so it is safe to add a few lights and sprinklers. There should be an exterior outlet by the back door. This can be extended with a waterproof box and tapped with counduit which will go under ground to where it is needed. Similiarly the water pipe spiggot in the back yard can be removed and extended with a “Tee” sending a water line under ground to where you want to locate the sprinker control solenoids.IMO a split system of irrigation is better. If you have one timer for both the front and back yard you have to run a solenoid control wires to each is all.
