I have a 2 year old daughter and want to move out of Arkansas. and have some big custody questions Please help?

Right now I live with my 2 year old daughter in Arkansas. I would like to move up to Colorado with her but I need to know what needs to be done ahead of time. Her father and I don't have custody papers or anything like that because he didn't want them to make him pay child support or force him to take her when he didn't want her. He takes her anywhere from a couple hours to a day and a half every 2 weeks or so. He does not pay child support but he does buy her pull ups every couple months and I pay for the rest No I DO NOT want to take her from him completely and Im not doing this to make him pay child support I just want to know what needs to be done ahead of time so I know how to go about this situation. I know no sane judge would give him custody because most of the time the reason he doesn't pay is because he spends all his money on weed and the reason I kicked him out is because he threw me against a dresser when I tried to walk away from a fight. Something I have pictures of the bruises from. Now again My daughter loves her father and I would never stop him and her from seeing each other as much as possible I just need to know what needs to be done ahead of time so I can prepare.