Fig - why does your attorney say you are in for a battle? It sounds pretty cut and dry that the mother is not fit to be a responsible parent.
Frank - how much vacation do you get in the summer? My divorce judgement has both of us for 3 weeks each, but there is some stipulation about if we stay in town that it is just 2 weeks.
You should make sure there is the right of first refusal.
I agree with others - if you can peacefully coparent, I suspect your X will offer up more time with the kids so she can have more of her own adult time.