Back when I was in good shape, I was regularly running a loop around the principal parts of Cougar Mountain Park. This was my favorite run. It starts at the Red Town Trailhead, which can be quite crowded on weekends. I have never found the parking lot completely full, but sometimes nearly so.
The run starts up the Red Town trail, which climbs steeply at first, then levels out. At this point I sometimes go up the Quarry Trail, or if I am more ambitious, the Shy Bear Trail. Either way, the climb is steep. I aspire to be able to run the qhole way, but I have not achieved that yet.
Fred’s Railroad trail is wide and flat: a respite from climbing. The easiest alternative is to continue on Fred’s Railroad Trail, around Klondike Swamp Trail, and back down Coyote Trail and Cave Hole trail. But the “full” outer loop takes a right up East Fork Trail, another moderate climb, until it crosses Clay Pit road, and into the northern parts of the park: Tibbetts Marsh Trail to Shangri La, past the Anti-Aircraft trailhead, and down Coyote Creek. Back at Clay Pit road, it is possible to return on the Road, to the unsightly and depressing unfinished development on 166th Way, and down Military Road to the trailhead. Cave Hole trail is a lot more scenic.
Map: I did not start my GPS at the beginning, so this starts at the turnoff from Indian trail.
GPX: Outer Loop