That's exactly how I plan my senior year to be. This year, my junior year, is going to be hard due to the SATs and such. ;___; But my senior year will be ultimate senioritis, because I saved up all my study halls for it. I'll only have to go in for half a day. And most of my classes will be classes I adore, like AP Art and Honours Choir.
The hardest part of my senior year, really, is just going to be having to make my portfolio (for photography) and do my audition (for music) for college.