We have Gone Pres week the last 3 years. Last year, these fares opend up on 9/24. Immediately, the only thing available were the most expensive fares for Fri, Sat, Sun of both weekends (from BDL) As others have said, I think it ends up being aroung $400 RT. Within a month, there was no availability. However, we have always flown down on Monday and Tuesday of Pres week and returned the following Tues or Wed and been able to get fares under $250. So having the kids miss just a couple days of school might be the best way to make it work. Also, in both years, while I booked initially when the schedule opened up, (at around the Fun Fare rate), I was able to later switch to a cheaper rate, with only minor changes in flight times. IN 2004, I did down Tues and back wed, in 2005, down Monday, back Tuesday. I have never watched MHT (too far away), but you it may be worthwhile to check that out since I believe their winter break is the week after MA has the winter break. Of course, alot of people from MAss fly out on MHT, so I don't really know if that will be helpful.
Good Luck!