<p>Read AMSCO. If you read at 3-5 chapters a day (maybe take some days off school before the test =)) you CAN do it.
I would read the chapters, answer MC, and practice at least 1-2 DBQs from the post civil war time period, in addition to a couple free response questions.
It all depends on how many APS you are taking. If AP US is the only one, then I think you can do it if you work work work. And SLEEP IS IMPORTANT!! no matter how much you know, if you are too tired to remember, than it is all for naught.</p>