Just keep working hard. Don't worry about the AC year yet...get through the summer first.
That being said, you will take validation tests during the summer. I didn't find them very hard at all, and ended up validating Calc 1, Chem 1, and a year of German. I later validated Naval History with my UW transcript.
I would suggest placing physical conditioning as your top priority. Not only to help with the PEP and stuff over the summer, but if you're in good shape, the lack of sleep and constant activity won't wear you down as much. The Plebe Hack gets everyone...don't even try to avoid it. I got it the second week of the summer and had it until the second week of the AC year. Needless to say, it sucked, but I didn't let it affect me a whole lot.
Best way to prepare yourself? Enjoy your last months/weeks/days/hours/SECONDS of being a civilian...with a car..and jeans. Live it up.