WE did lunch last year and are doing lunch again this year. Last year it was only in Downtown Disney so we went from there to MK. I believe her appt was at 9:30 and lunch was at 12:45. We made it in plenty of time.
This year we are doing BBB in MK at 9:50 with lunch at 12:35. That should be good timing as well. We have the big package too, with the dress and the picture taking. We did last year too and still had plenty of time.
Personally, I loved the lunch. Cinderalla does not walk around at lunch. At least she didn't last year. It did get hot for my DD4 in the afteroon with the dress on, but she would not take it off. We went in April, too, so it was warm. Other than that, it was perfect. That is why we are doing it again this year. And with the one in MK open, it is even more convenient.