Hi Chicagomum, I too think you have several things going on here and they should be dealt with separately. First, the meddling MIL. Why don't you signyourself up for loads of activities and make yourself genuinely too busy but reserve say one morning a week for MIL. In fact, this migh serve to save you some childcare cost when you are back at work. Perhaps you could use her one day a week for free???
Secondly, DH taking her side. Well, just stand up and say your busy but you could be around on x. If she stops by unannounced just make like your on your waqqy out the door, smile, and say "ta ta".
Are you going back to work full time? I wonder if some of this might sort itself out when you are busy at work.
As for where you live, the quality of schools, etc. I completely agree with you. These things should be considered long before the children are actually oldenough to sign up for school. I think you have 2 and they are quite young?
However (I have to be honest here), didn't you just move back from Chicago? If so, are you in a new house? If I were your DH I might be a bit irritated with having this conversation after we had just moved backk ffrom Chicago. I would think the time for this conversation was before we moved back. Now if you just returned to the house you already had before going to Chicago, then I retract this paragraph.
One more point, is it possible that your DH is looking for YOU to stand up to his mother? Possibly if you lead the way, he might be more willing to support you.