If we were true traditionalists of the sport, it would be by reading the following day's newspapers: if that had been our method, Monday's stage would have been great.
In terms of the method: either while on my turbo trainer (Rouvy on laptop one side of me, Eurosport on Chromebook the other) or on a small screen flipping between race stream, CN forum and (if I have been away from the screen for a while or am catching up and want to know if I can safely fast forward) PCS livedata. And sometimes twitter as well. Plus whatever I am meant to be doing. And wearing headphones so as not to disturb Mrs Armchair.
Until this year, Eurosport via a BT TV package; this year, Eurosport player; next year, probably GCN Pass, because I really don't see myself ever watching the other sports on ES.