Hi!
I live "in" Dallas (not in the suburbs), and here is my two cents:
Unfortunately, Dallas is not much of a walking city and there isnt any place in Dallas that I know of that really fits that criteria.
You could look into the M Streets and Lakewood. Both are great neighborhoods not far from THREE Targets! And - there is a Trader Joe's under construction on Lower Greenville, which in the M Streets and real close to Lakewood.
DISD schools, in general, are considered "bad" but the elementary schools for the M Streets and Lakewood are GREAT. In addition, DISD has an excellent Magnet program for middle and high school, and 2 of our high schools are ranked in top ten in the country, and a few more in the top 100.
There are several nice private preschools in the Lakewood area. I would just google Lakewood Preschools and go from there.
Also - can get to Irving in @ 30 minutes, and in close to lots of cool restaurants, White Rock Lake, the Arboretum, and the Dallas Zoo. And, of course, the swanky North Park Mall - where there is always some good people watching...
Edit to add: Please check out Dallas itself, and not just the suburbs. I am THRILLED with my neighborhood and my Blue Ribbon neighborhood school and think all the people in the suburbs just don't know what they are missing.