I have a small fruit tree orchard that is also used as a park setting for dogs and children. I would like to put drip around fruit trees but keep the sprinklers in use to water lawn.
Please be more specific on what you want to do and how large is the park.
From your posting, I get that you want a sprinkler system to water the grass, and a drip system to water the trees.
I would keep the two systems separate, feeding off from two supply valves, because of different watering needs and schedules. You will need a timer to control this. Also, since you described the area as a high traffic area, I'd bury all pipes.