You can’t quit something that has no schedule or time frame. Her FaceBook page, is pretty clear about what she is doing.
FaceBook - Sarah Palin:
Sigh* Reports of Tour Demise Are Greatly Exaggerated
by Sarah Palin on Wednesday, June 22, 2011 at 4:14pm
Imagine our surprise when reading media reports today that the “One Nation Tour” has been cancelled. Why didn’t anyone tell me? Oh, wait, that’s because it hasn’t been cancelled. (Good ol’ media... you never cease to amaze!)