I have a parenting plan in place I'm ordered to stay in the same state as my sons father. I'm wanting to leave the state to be with family and support. He isn't paying child support (which he is ordered to) he's 4 months behind doesn't visit his son. I'm wanting to know the process that I need to go about and how likely a judge would approve it to let me be with family and have help with my son

The process is to go back to the court and ask for a modification of the parenting plan. Keep a log on his missed visitation. Generally visitation and support are separate issues, so you need to show that a) the child will benefit from the increased support system and b) that the father is not using the visitation granted him.

You cannot leave the state without court permission. That will put you in contempt of court.