High Park offers, not only a great place to walk, but also free tennis courts, free swimming pools, and a free zoo.
The Shakespearian plays in summer are a good time, and the pond is decent for fishing.
The restaurant in the middle is a good place to breakfast, taking advantage of their early bird special.
The only down side is the parks biggest draw. It can be hectic during cherry blossom season. You'll love it, or you'll hate it, but the rest of the year is a true delight.