I studied Tae Kwon Do in Waukesha Wisconsin for 13 years.
What I would recommend is go to the class at any school you are thinking will work. Watch the entire class. How much personal attention is given to the people not wearing belts, or wearing white or yellow belts.
Good schools will usually spend a lot of personal time with the lower belts making sure they get a firm foundation.
Our classes spent 15min warming up. 20-30min doing the fundamentals 15-20 min sparing etc. and then a brief cool down for the average class. There was a lot more emphasis on fundamentals than sparing in the average class. Two days a week there were more advanced classes which spent more time on sparing, and other self defense techniques as applied.
It's hard to quantify what makes a "good" school. It's a lot like firearms. What works for me, may not work for you.
If you would like someone to come visit a potential school with you. I would be happy to tag along schedule permitting.
Hope that helps....