Met a couple couples in Palmer Park south canon parking area before. Though it seems mostly a cruising spot for gay men.

Is this on an actual walking trail? What time of day did you go?

There are 3 separate areas to park at and you can go through the bushes or up on the rocks to secluded areas. They started closing the park at 9pm now unfortunately but I used to go there after dark when the weather was warm throughout the summers.

The only other real options are the arcades at Pleasures or Ambassador.