We (me - 67 yr old grandma, daughter age 42, and granddaughter age 9) took the Paris/London tour this past summer. First of all granddaughter is quite shy when it comes to meeting new kids - yet the first nite, she latched on to another girl and her brother from Illinois and they were inseparable for the entire week!!
The seamless transition of kids back to family groups and also time with JUST the other kids, seemed to make for a real comfort level for her (and us!!) All in all it was a super trip and we each got to enjoy and relax in our own way.