mouseclick1: I just bought our flights down. I agree with others that you don't want to have to do a lot of driving in the upper midwest in February to make your flights. About half the time, we're headed through a snowstorm to make our winter break trip.
Instead, consider flying from DTW, but into TPA rather than MCO; prices there are often a bit more reasonable, and it's only an extra 45 minutes each way (provided I-4 moves well---which doesn't always happen, thanks to construction). It won't be $175, but I got $250 pp on NW (where I prefer to accumulate miles), which for a Saturday to Saturday trip in late Feb/early March with direct flights, without having to fly first thing in the AM or late evening---that's not bad. The same weekend to MCO for anything approaching reasonable flight times was $330pp and up.
Last year I snagged $200 RT for good times, Sat-Sat during President's Week on Spirit (into MCO, back from TPA), but at the moment, except for the dead September, Spirit's minimum weekend price to MCO is about $250, and *some* weekends (but not all) into TPA are $200, and many of those are lousy times---as often as not, NW prices out less than Spirit, and since I'd rather fly out of WorldGateway, I'd rather collect my NW miles, and I find Spirit's planes to be less comfortable, it would appear that Spirit is not currently a good bet for me. AirTran's prices, whether out of FNT or DTW, are consistently higher than the other two for the dates/times I've checked.
Granted, there may be a sale on Spirit or AirTran that pushes them to or below $200 for my dates. But, given the steadily increasing fuel costs, the continued recovery of leisure travel, and the success of the Happiest Celebration/MYW package promotion, I decided that trying to hold out for $200pp was not as likely to pay off as it was last year.
So, I figured rather than wait around to see if I could save $100-$200, I'd be better off limiting my upside risk but getting the times I really wanted, especially as the fare buckets on NW were starting to dry up. I got the last tickets at that price on those flights, so I'm pretty happy. When my kids get a bit older, we can start taking the early AM flight down, or the late evening flight back to save a few bucks, but they will be 5 and 7 in Feb, which for the younger one is still touch-and-go when you disrupt his sleep times.
If you want to save a few more bucks, you can fly USA300 from DTW but into PIE (just a bit farther than TPA) but they don't fly every day. Depending on where exactly you live, you can also fly TransMeridian from TOL to SFB. They are also a charter, but that time of year they fly daily.
If you are truly stuck, and are still willing to drive, try driving to DAY or CMH. Delta flies direct from both airports. NW even has a single direct flight CMH-MCO for those February weekend that, when I looked were $200 pp. At least going to those two you are driving south rather than east---and hopefully away from any snow.