Go back to spin! Just take it easy the first couple of classes...you'll be able to get back into it quickly.
I am currently in love with swimming! I hadn't been in the pool for years but I went back last week and has so much fun!
My schedule is 4 days per week - 1 run, 1 spin, 1 swim, 1 walk. I need to get back to the weights but I haven't quite gotten there yet!