Don't worry about NAPLEX until P4 year. I would just take it easy and do stuff you like now since you'll have a lot less time once matriculated. Only thing I would do is maybe, meaning don't really have to, glance over those top 300 drugs if you don't have any retail experience. If your the type to worry/want to stay studious somewhat. You'll get tested on them during your community labs.
I guess best advice is listen to your school's suggestions and contact former/current students to see what their recommendations are.
Take it easy and enjoy.