For some reason, the UC system seems to avoid letting undergrads run a course. They let undergrads be a 'helper', but are very careful to avoid letting undergrads teach, at least in my experience.
As for taking a year off, it's a great idea. I wish I had. It will let you have some time to breathe, make a bit of money, spend some time doing something new, and will be great for your resume. I don't know if it's better or worse than teaching; I tend to think it's just different. There are a lot of students at UCB that took a year or two off between undergrad and grad school to work.
And, enahs, don't think that big fancy schools like Berkeley are all they're cracked up to be. I'm glad that I got the professor I did, but if I had it to do all over again, I wouldn't have gone to graduate school here.