Try putting the sensor on the back wheel, it should work just fine. I work on my trainer last winter and did find the speed and distance to be very useful. My computer also had a sensor for cadence which also was a big help. Find some good training videos and enjoy. By spring you will be pleased at how much better you ride those first few outings.
i road 30 minutes each night after work at about 18 mph and felt it was a great workout for a 61 yr old guy. For some fun change of pace I would watch tv as I road. During the commercials I would sprint one commercial and recover during the next. Most of our commercial breaks are made of 4-6 separate commercials lasting about 30-60 sec. So it was a good interval workout.

Mike