I'd imagine this park is being built similarly to motorsport ranch in the DFW area.
http://www.motorsportranch.com/
I have a couple of friends who have memberships at MSR and IIRC as a member the track is "open" to you anytime they are not having a club or other event. I believe you do have to block out some time but otherwise its open. However they often hold club events and other track day type events so its not always closed to the public. Its a nice facility and IIRC they were planning (or might have already started) to build homes around the course as well... similar to having a house on a golf course!
I'm sure the new park will offer some nice options for getting out on the track for joe. avg. Don't forget Heartland Park often hosts many club and track days that are open registration too. Its not that far of a drive. So potentially with the new park and Heartland there could be some serious motorsports action available to the public in KC in a short time.
Yay for roadcourses!