We would like to take our two daughters (ages 15 and 18) for a 3-4 day vacation within driving distance from Wisconsin. Anyone have any ideas, other than a shopping trip (they do enough of that)?

How about Cedar Point Amusement Park in Sandusky,Ohio? Followed by a day trip to one of the Lake Erie Islands and on to Cleveland to the Rock and Roll Hall of Fame.

www.cedarpoint.com
http://www.put-in-bay.com/

Have you made many visits to a college town? I imagine you've been to Madison since it's right in your fair state. There are other nice college towns in the midwest. With kids those ages...Others might have suggestions for towns to visit.
Also check trip advisor.com. You can put in your town and they'll send you suggestions of places to visit.

We love the Midwest and enjoy going back to many different places there. Of course there is always Chicago which is great and agree with Galena and also like the Lake Michigan Shore Area of Michigan and of course Mackinac Island. We also really enjoy the Amish Area of Holmes County Ohio. We frequently go to Kansas City and enjoy it there. We also love Minnesota. It is pretty along the Mississippi River and on into Mpls. and St. Paul and also love the area up around Duluth and the North Shore. It kind of depends what your daughters like to do. We took our daughter on a tour of college campuses in the Midwest and that was fun. There are many and they are fun to visit. By the way we loved your U of W - Madison. Really beautiful campus. Whatever you decide, have a great time.

I'll second Cali's suggestion regarding Mackinac Island! When our kids were about that age, we spent several days at a B&B there one summer. The island environment gave our teens the freedom to move about idependently and there were enough activities to keep them busy for that amount of time.

Can you tell us more about your teens? Mine would die if they were forced to spend 3-4 days in an idyllic country setting. Do they like music? Amusement parks? Theatre? Sports?

I think that your girls would love Chicago. There is a ton to do besides shop but they can always shop too if you run out of things to do. There are lots of great museums, you could go to the zoo, Navy Pier, see a show, lots of great restaurants.

The Chicago area is a good idea if you have not done it several times. A fun summer afternoon is a day at Arlington Park watching horse races. Spend the day at 6 flags. You can catch a minor league ball game in Schaumburg...or you can do the downtown stuff already mentioned. OR....

How about St. Louis. Great river area, go up the arch, etc. Can be humid.

Depending on your desire to drive, South Dakota black hills is a nice family trip that could be done with 3-4 days there but probably another 2 plus for driving. OR...

If everybody is outdoorsy...A canoe trip in the Boundry Waters. You can also rent a houseboat on Rainey Lake, MN although there may be a longer minimum on that depending on your timing.