K.L.
MzKitty has the right idea. Call ma in law, and tell her you want her to plan their party and tell her when you will arrive. Stay for the weekend at her house and let her have the kids the whole time. Go shop, to the spa, out with hubby for dinner, relax and have fun, and let the kids spend the whole time with grama and then pack them up and leave as if it never happend. She will love telling all her friends that she HAD to do everything because you just didnt have a clue how to deal with it. haha.
or be glad they have grandparents living and so close. being able to have grama at a party would have been nice for my kids. it never happened. I didnt get along great with her, but I would have liked her to at least admit my kids were her grand kids..once.