There is some great advice here for your first rando ride. Road riding just isn't possible where I live for a good four or five months, so I spend alot of winter hours on the trainer. I use the Kurt Kinetic with the Inride power meter thingy, and paired with Trainerroad it is great. If you have family and work and other commitments, it is a great way to maximize your training time. You can get a great workout in an hour without spending too much time pondering weather, putting on layers, gearing up, etc. Of course it is not the same as putting in lots of outdoor miles, but it is an excellent real world compromise for those of us weather and time issues. After a winter of two or three high intensity trainer rides per week, I don't have too much trouble getting back into the swing of things when spring time comes. If you can pair weekday trainer rides with a long ride on weekends, you should be ready to go by March.