Wasting time "prepping" prior to law school is stupid because you don't yet know how to "think" properly. You're going to handle it like undergrad, and you don't know what you are actually looking for. You won't understand the system. Yes, you can read "law," and yes, you'll pick stuff up, just like I know a little about my car's engine, having read the owner's manual, but you'll focus on the trees without realizing no one gives a shit about the trees - it's the dirt thats important.
Maybe it's difficult to articulate, but I see it now when I talk to non-lawyers about legal issues. They'll be going on about what they think is important, and I'll realize the issue is notice, not liability. Try and explain that and they'll see injustice, when in fact notice is step one in justice.
The only way to learn what you need to know is to see someone get humiliated in class when they can't explain why the court remanded the case after seeming to agree with the trial court's summary judgment legal analysis (hint: mixed questions of law and fact are inappropriate for summary and best left for the jury).
Like people said on page one - smoke dope and jerk off. You won't have as much time as you'd like for either once law school gets rolling.
Moreover, I can see how it'd be a hindrance to "prep" - now you think you know something and might tune out things that don't conform to your expectations - but the unintuitive is important! You may not be able to absorb what you REALLY need to know. Meanwhile, the jerkoff stoner is soft clay ready for shaping and open to the fact that he doesn't yet know shit (and isn't a douchebag, super-proud of all the "prepping" he did over the summer while everyone else was just jerking off and smoking).
And reading while baked can be fun and productive - you may even have "ah ha!" moments - reading while drunk is literally not possible.