Glad you found them! Highland Park has 2 circles that surround it but you have to drive into the park proper off of N Highland Ave to drive around Reservoir Drive. The activities are interspersed between shelters.

Reservoir Dr can be easily mistaken for Lake Drive, which surrounds the park in whole, not just the reservoir. Lake Dr loop has a stocked pond, dog park and swimming facilities but does not require you to enter the park to access. You want Reservoir Dr. Just type in 120 Reservoir Dr on GPS, it’ll take you to the first activity.