Thanks for all the replies!
I did my first indoor season on my new Kickr Core. Because of the fitness gains, I decided to buy a power meter for the outdoor season, but hadn’t install it yet to my bike. So I was unaware of the combination of power meter and the TrainerRoad app for an outside ride. Thanks for the clarification!
Oh man, sorry to hear that. I use a Topeak ridecase together with the center mount. I’m satisfied with its performance, altough a proper head unit is, in my opinion, the better solution regarding battery life in the long run. On the other hand, I prefered to invest my money in an indoor trainer and 4 months later into a power meter and stick to my phone mounted to the handlebar. 300$+ for the better battery life is not the best bang for your buck to me.
@Bryce and @NervousNinja:
some Level of integration between these third parties and TR app for outside workouts
would also be appreciated from my side. Because, like i wrote above, the purchase of a proper head unit is the least attractive to me in comparison to a power meter or an indoor trainer. This would, in my opinion, create a lower threshold for beginners on a budget to engage in outside training with TrainerRoad, instead of cancelling the subscription during the outside season. But I’m also not aware how much manpower you need to implement such a feature.
So, my conclusion for the budget rider with a power meter and a phone mounted to the handlebars, who wants to do structured training outside, is to use the TrainerRoad app for the intervals and run Wahoo Fitness (allows to record HR from a Bluetooh HR-monitor) for GPS and HR data in the background. Later on, you can upload the Wahoo fitness recording to Strava.