Last Friday we left Madison at 4:00 for the Brewer game. The traffic backup began a little bit west of Lake Mills and it took us 55 minutes to travel 7 miles. We reached the MP parking lots at 6:30. Given our experience, I would be surprised if you could leave Madison at 5:00 and not be late for a 7:30 concert, on a Friday night. Coming back from Madison (before the I-94 crossover lanes were built), we had decent success taking the Hwy 16 exit from I-94. 16 goes around Pewaukee and Oconomowoc, then to Watertown. In Watertown we took Cty A which got us to Lake Mills and from there it was easy to get to the interstate. While we were stopped in EB traffic last Friday, we wondered if we shouldn't have tried taking that route in reverse (exit at Lake Mills, then take A to Watertown, and 16 back to interstate) - but since the backup starts west of Lake Mills, I don't know if that would have done much good. Other roads may be available (like 18 out of Madison? nope, that's closed at Jefferson), but bear in mind that up to 3" of additional rainfall is expected from Thursday night into Friday night. Smaller highways that may have opened since last week may be closed again by Friday afternoon if enough new rain falls by then. If I were in your shoes, I'd try to leave earlier. If that's impossible, I'd keep checking the DOT road closures map before you leave Friday, and if you have a good, detailed map (like a DeLorme gazetteer) or a GPS navigator, bring it along.