I've been using TrainingPeaks for some years and like it very much. I do both indoor and outdoor riding using a Garmin from which I upload my data to TP. Indoor or outdoor doesn't matter to TP, especially if you are using power, which I'm guessing you are. TrainingPeaks includes many inexpensive training plans, tailored for various purposes and riders. TP has helped me understand the affect various training routines have on my fitness and readiness to train more. I mostly create my own plans there, though I have used TP plans also. One needs to have a premium account. The free one doesn't do much other than give one a place to record rides. There's other good software out there which does much the same thing.
For outdoor riding, I think cadence and speed sensors are a good idea.
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