Magnuson Park Has A Dog Beach

Magnuson Park is worth saving for a warm Seattle morning because the off-leash area includes access to Lake Washington. That makes it more than a neighborhood dog walk without requiring a second stop.

I would keep the plan simple: park, do one loop, let the dog decide whether the water is interesting, and leave before the lot gets busy. A regular leash still matters for the walk between the car and the fenced area.