I would write a note saying that, as always, she can reach you by cell number and that the kids will be spending the week at your address, here it is, and here are any other numbers you want her to have.
Leave it vague, reassure her (reminding her about the the cell phone and any other details you feel comfortable sharing) and protect your boundary
She is prone to look at life a few inches off the ground (problem-solving is hard) so having control of details probably gives her comfort. You and the court order are capable of seeing life at 30,000 feet.
The goal is to address her perspective without giving in to the point she runs things.