I'm thinking out loud here... The problem I see is there is no power or speed data in the FIT file. I think a "trainer" file needs to have something to chase. For example, I can create this same course in
and declare an avg speed on the flats and a climbing speed in feet/min . The course time is roughly calculated based on the climbing. If I download this course to a Garmin unit, the virtual partner will slow on the hills. By increasing the climbing speed I can challenge myself more and more.
Of course this would work perfectly with a trainer that has controllable resistance. On my KK I would have to speed up in order to maintain a certain power level and there would have to be some kind of override to keep me from flying up a hill. That's why I thought linking to power not speed might work.
Unfortunately tcx files created as courses at bikeroutetoaster will crash GC to the point it won't even start again until you delete the file from the folder of rides. So I can't test any further.
So far, I've tested against rides I've completed so I just follow a ride I already have. I suppose I could add the FIT file, ride against it then delete the FIT file leaving only my actual ride. However, a separate workout section of rides is needed.
Luckily, living in SoCal I won't have to resort to the trainer very much. However, the prospect of doing my few trainer rides against rides I've never previously done is enticing.
Fernando