I would ask your daughter if she wants to goon this trip. She should have the right to say no if that is how she feels.
I second getting her counseling. Divorce is difficult for kids under the best of circumstances.
I also benefited greatly from counseling. It helped me get past the points where I got stuck.
Do you have an attorney? If not, get one! If yes, let the attorney do your talking. THat is what you pay them for. Don't believe all the tripe your AH tells you either.