I'm working on how to check in as many times as possible online. I'll let you know if/when we pull it off.

By the way, there is no need to live in a hub. Although we live in Minneapolis, we would fly in to Detroit on Friday night, overnight at the airport, complete the mileage runs on Sat/Sun and fly home Sunday night. We called NW and found out that the cheapest B fare between the two, with a Saturday overnight, is $196. We are looking into booking eight Sat/Sun overnight roundtrips, with every other one being DTW-FNT and the alternate being FNT-DTW so that we would always have a ticket on the next flight out. At this point, we are investigating what, if any, rules of ticketing we would be breaking. It looks like we would be okay.