Well, according to Mapquest, not too far. Maybe 1300km? I didn't plot it out totally, but I know it's 1200 or so to Madison, and looks like not too much farther to the 'Fest. Easy day's drive AFAIK.
I'll double check it on one of the NAV systems up front (they can plot a turn by turn destination in about a min, and give total KM).
Gus
My advice:
Since you will likely be passing through the Minneapolis area on your way, you do need to consider rush hour traffic. Some of the bottlenecks you will want to keep in mind:
I-94 through downtown Minneapolis. Narrows from five lanes eastbound to two near the tunnel, then three lanes through the tunnel.
I-94 east of downtown St. Paul. Near the 3M headquarters there is a segment with only two lanes in each direction, with three lanes each way in both directions. A current construction project will rectify this problem.
I-694. Narrows down to two lanes in each direction at I-35W, then three lane shifts, the first between I-35W and Lexington Avenue, one in advance of the exit to south I-35E, and then another between the exits to north and south I-35E.
In addition, people in the Twin Cities area do like to leave down during the day on Friday of a holiday weekend, and you also have the Minnesota State Fair during this period. Plan accordingly; I would advise trying to time your drive to get through the Minneapolis area before about 6am if you are passing through on Friday.