Riverside Park is one of Indianapolis' older west-side parks, spread along the White River with open lawns, sports fields, playgrounds, and paths for a low-key walk. It is not a headline sight, but it gives a useful break from museums and downtown blocks if you are already exploring the near west side.
The park also sits near the Major Taylor Velodrome and Marian University, so it can fit into a wider loop through this quieter part of the city.