Wait for her to come looking

No one leaves a bag filled with specialized equipment around on a college quad without running back to get whatever you lost as soon as you realize you're missing it. Who knows, maybe she needs to milk herself sometime soon.

You sit around by the tree and wait. No classes in the next few hours, which leaves you critically and happily free to meet with any approaching milkmaidens. And by "no classes" what you really mean is "no classes that you wouldn't skip at the prospect of meeting this girl.

So you wait.

And wait....