As we are considering base training, the training is not intended to be anything like your actual events – was it racing or triathlon or fondo.
The important thing here to take away is that your body doesn’t work in such a way that you train only what you want to do. In other words, threshold training is not only for time trialists and fondo riders don’t only ride easy endurance pace. The central aspect here is that by increasing your FTP, you increase your ability to work in all levels. That is, if you do a fondo with power around 70% of your FTP, by raising your FTP, the 70% is faster. That is why most cyclists can just work to increase their FTP.
That is why your training can contain things that you will never see in your actual events. Actually, most interval training is something that will never happen in any event. For instance, I do road racing and I have never needed to do 10 mins at threshold – but I have trained those quite a lot. You’ll soon face the 3 min VO2Max efforts and they are also not specifically for your fondo but just to increase your FTP.
In a nutshell, during your base, don’t skip any workouts as something you don’t need. You need everything there is in the plan to get your body to become faster. Only when the time comes for your specialty phase the training becomes more like your actual fondo.