For me, I find that the "getting outside" part is an integral part of fighting off depression. Sure swimming, lifting and occasionally spinning are "better than nothing", but I guess I just need fresh air and sunshine to complete the experience.

In the winter, I do a LOT of running (easier to sqeeze in a quick 30 minute run during daylight hours) and xc skiing when we have the snow. I also like to mtb at night, I feel safer in the woods than out on the road--good lights are still a must. It's warmer in the trees too.

I can NOT spin 5X a week....ick! Either on the trainer or on the bikes at the gym. That's just me (ADD girl!). I mix up my indoor workouts with swimming, lifiting and yoga.

As far as finding/listening to a Spin instructor; ask around at your gym and find an instructor who actually rides a bike. Someone who also is a cycling coach will be best. If you can't find such a person be very careful about following the "aerobic-instructor" type spin teacher's instructions. I've been in classes where the workout given was NOT cyclist-knee-friendly! I avoid all that "jumping" up and down cr@p. I just let the instrutor know before-hand that I am a loooong-time cyclist and that I know my body well and that I will not be doing anything to harm it.

As far as spinning getting you ready to race....uhm well no. I mean it will help to keep leg-strength and fitness, but it does not help with bike and pack skills. I always feel rusty when I return to racing and riding with a group after a long winter. As long as the roads are dry and it's above freezing, I still try to get out on those group training rides at least once a week.