Grandparent Custody for Disney World

Maternal grandparents have asked me via an email forwarded by my ex-wife if they (grandparents) could take 2 of my oldest kids (daughter 8 and son 6 years old) to Disney World in Florida for a week. The trip would overlap part of my visitation weekend (every other weekend) so my wife proposed rearranging her and my custody time to accomodated trip to Disney. I responded directly to grandparents declined stating I have a conflict (which I do). I subsequently emailed my wife stating that I had responded directly to the Grandparents. The Court-appointed Parenting Coordinator (P.C.) asked me to clarify the nature of my commitment with the kids during the weekend in question and if it could be moved. I ignored P.C.'s email believing she was out of her jurisdiction since this was a matter between me and the grandparents - not between me and Mother.

P.C. ruled that grand parents could take kids out of state to Disney trumping my overnight camping trip (similar to Boy/Girl scouts) previously planned with my kids. She has not ruled that the kids could go to Disney - only ruled that IF they go to Disney then the custody rearrangement proposed by my ex-wife would stand. I am seeking Judicial Review of this decision but not sure how to base my case. Frankly I’m not comfortable with my kids being with grandparents for a week without any parental supervision. I don’t trust them as they have been “case building” for 3 years (including 1 year prior to separation). The P.C.s decision seems fundamentally wrong but I don’t want to sound like sour grapes and declining trip to Florida out of spite. Can you suggest the argument I need to make in my Motion?

Thank you.