I use this greenway a lot and is a great alternative to running on the road and having to watch out for cars. There are many entrances, but I usually park off a gravel lot over off of Margaret Wallance and run underneath Independence Blvd to get into the park.
The 5K course is great with markers in kilometers and miles... there's a great hill in the middle of the course marking the 1.5 mile mark. There is also a big pond in the middle that a lot of people use to run loops or fish in.
Tip: look out for signs because sometimes this location occasionally has an event where the trails are closed or the main parking lot (off of Monroe Rd) is jam packed. I think they still run the Wendy's Invitational here for HS cross country teams [in October] and they even have some college events here as well - good for watching runners and races... bad for if you are trying to get in some exercise yourself.