A.H.
I feel your pain! We have attended church all our lives, and it was still VERY overwhelming for us after a move. I attend Carriage Hills right now (although we're about to move to Arkansas). I've been to Colonial Hills. At Colonial Hills there are lots of kids, but I don't know how easy it is to find a whole family of friends. At Carriage Hills there is a nice, very welcoming group of parents around your age with kids about the age of yours. Our second Sunday there we had an invitation to lunch with the gang, and we have very quickly established friendships.
As for MDO, I know Carriage Hills has one, but I don't know much about it. I have worked for five and a half years at the Mother's Day Out at First Evangelical Church in Memphis (at Ridgeway and Poplar). That has been an absolutely incredible experience for my family! We are currently full for the summer, but registration is underway for the fall term beginning in August. As soon as we get our contracts in from the current families (today and Thursday), we'll be able to determine our numbers and start calling down on waiting list. I have no idea how the numbers are looking so far, but if you want to call and check the number is ###-###-####.