Slow things down at River Park. Kick back with a good book or find a shady spot under a tree to rest for a while.
You'll be spoiled for sightseeing choice when staying in Pleasanton. River Park is a good place to start here, but there are lots of other interesting attractions to consider. Pleasanton Country Club, and Longhorn Museum are close to the recreation and green space and and will cap off your day nicely.