Originally Posted by Aviatrix

If you want to spend some time travelling together at the end of your daughter's stay in Schengen then the one way in which she could extend her 90 days is by taking a few week-end breaks outside the Schengen area during her stay. Any days she spends outside Schengen can be tagged on at the end - so if she takes ten days' worth of week-end breaks outside Schengen (say in the UK, or Ireland or Croatia) that would give her ten days she can tag on at the end.