I have seen corns and other snakes do this for no apparent reason. Sounds like she is in major growth mode too, during this phase I actually feed small meals twice a week, though many take issue with me for that. I figure in the adolesent state snakes in the wild probally eat as often as they can to fuel growth.

Many times though snakes just start cruising for no apparent reason. It is getting close to fall and burmation in the wild so even if well fed her biology may be telling her to seek more mouses and lizards for winter's sleep.

Anyway nothing to be concerned about, enjoy seeing Zim rather then just a coil under a hide,