Go full time. I'm from the East Coast and I had no idea there was even an option for part time so I have no idea what odd school you're trying to go to. Over here, it's you either go to school or you don't (aka dropped out). The only remote exception is trade school stuff for half a day (Vo-tech) and then the rest of your classes for the rest of the day. Even with that you're learning for the full school day.
Get some actual interaction with your peers so you don't end up that super socially awkward kid who was home schooled until college. Sure, there are some people who make out ok being home schooled for their entire lives up until college, but they are far and few between. They also did a LOT of extracurricular activities like team sports for 10+ years and balanced it out. You're going to need that knowledge to make it in the real world and college. If you can't deal with people properly you will have it pretty rough trying to get jobs or internships through interviews etc.
---------- Post added 2013-05-01 at 05:16 PM ----------
Wouldn't that mean you wasted your time since you worked hard in high school then? You were still in high school...
Also, only senior year? There are AP/IB classes starting from 9th-10th grade now for college credit (by now I mean when I went to school and I graduated almost 9 years ago) if you're worried about wasting your time unless it's for potential college credit.