Can you just not go to some classes? Or have friends sign you in, etc?
At one point I decided to do my Bachelor's and Master's at the same time. Eventually I figured it was a waste of my time, but I could still get it done with pretty good grades. Save for a few classes that I felt I really needed to sit in and listen, I skipped the rest and taught the material to myself via google, powerpoint slides or examples from the textbooks. Most of the classes didn't require attendance as part of the grade. The others I just told friends to sign my name in.
Even if you couldn't find a way around this, I'd still recommend staying. That loan is a big factor. Plus you could always just mentally check out of the actual class when you're there and work on your own ideas in your head. It would be a plus if you could bring a laptop to class hehe.