Trainer workouts are all about intensity, I agree. To me, the problem with trainer workouts is that you tend to push yourself into intervals/hard effort only when you feel totally ready for it, which makes it easier overall. If you're actually outside and you come up to a hill, you have to climb that hill (essentially doing an interval) whether you are ready or not.

That said, you can compensate for this either by having iron will and making yourself do, say, 7 intervals in 25 minutes.. or by getting a trainer exercise DVD. I recommend Spinnervals, they are extremely tough workouts and probably better than you get outside (if you do the exercise faithfully.)

It is tempting to think of the trainer in terms of speed/distance, but I'd resist the urge to do so. These things are so incredibly variable - I'd focus more on heart rate and effort. You'll see the improvement when you get outside.