Shared custody question, How far away should both parents reside? ?

The mother and I have reached to an agreement of shared custody during court ordered mediation. She gets them for 2 weeks and I get them for 2 weeks, alternating. There are no child support for both parties. We had agreed to live in the same school district for our children (This county has like 8 cities and 7 separate school districts). However, there is a point of where I'd like to live in a 15-20 mile radius in that county. Should I just say, we should live anywhere in that county (which expands our options of allowing to live in the country, work, etc...) Would I still be able to drive my kid to school 10 to 15 miles away? I have final court coming up in 6 more days and I would need to be prepared to face the Judge with the best options. I do not want to live in the same city as my ex wife lives in. I would like for it to be anywhere in that County. Is it possible? Please tell me why it is or not a good idea. Thanks! (P.S.) I looked up on gps and it said that the county I live in is less than 18 miles long ( 20 minutes) and 15 miles wide.