Her parents had stayed fairly tight-lipped during her disappearance.  Without knowing where she was, they couldn’t exactly concoct a good cover story.  Mostly they stuck to "oh, enjoying her year, reading lots, you know how she is."  After her meeting with the Secret Service, they’d settled on a half-truth cover story - she had an opportunity to take a year off and go backpacking around Europe.  She’d claim it was an excellent learning experience and that she was excited to finish out her last year of school, even if it was slower than her peers.