Time: 6:00am - Noon (check website, these times can change)
According to the MPRB's site, the following parkways will be temporarily closed on Saturday, September 8, for the 10:00am Mill City Suds Run 5K: West River Parkway and Stone Arch Bridge.
HOWEVER, I checked the course info, and it shows the route as being on the East bank - Starting at Father Hennepin Park, utilizing Main Street, looping around and returning thru Boom Island and Nicollet Island, then back to Father Hennepin Park via Main Street.
Either way - just be aware there's a race Saturday morning that may affect what route you take to get where you need to go! (Like the Mill City Farmers Market, for example.)
A complete list of parkway closures through December 2012 is available online.