Actually, from what I read in "The Ultimate Ride" by Chris Carmichael...

45 min on trainer = 1 hour on road
1 hour on trainer = 1.5 hours on road

For anyone who can be on a trainer longer than 1 hour, I say mucho bonus points!

It sounds like you have a computer? I have a rear-mount CatEye that keeps track of RPM, MPH, AveMPH, Distance, the works. That has helped me tremendously. I think I would be cheating quite a bit without it.