I don't think things would be easier for you and the boys if you moved to be closer to her. I think it would be less stable and chaotic. She doesn't call regularly. She doesn't maintain the current visitation schedule. She wasn't even prepared for the car exchange last month (no car seats)! I think she would expect you to do even MORE than you already do if you were nearby. I think she would stop by whenever she felt like it and would expect you to go along with whatever she would like. All of this is only my opinion.
Of course, in an ideal world, both parents would live nearby, follow a schedule, and work things out together. Unfortunately, she hasn't shown that she is able to comply with anything like that.
I'm glad the boys are getting the help they need (meds and therapy). It sounds like you've made huge progress with them.