You would think that the best way to train for long steady climbs would be to just do lots of long steady climbs. I don't think this is true though. I think the best way to train for this is to do regular interval work - anaerobic threshold intervals, SST intervals, etc.. This is perfect for a trainer (no wasted time dealing with wind, stop signs, traffic, etc.).

Of course, you have to develop an aerobic base also to develop the ability to ride for 4-6 hrs (ie. like one long aerobic ride per week with gradually increasing times). Then I would concentrate on shorter harder interval days (ie. 3 x 10 min, 2 x 20 min, 8 x 3 min, 12 x 90 sec, etc..).

You would benefit from reading this $13 book - http://www.amazon.com/Training-Racin...0&sr=8-1-spell