Anyone else try this?
I want to get some volume in my riding. I have 2 days where I can ride for a few hours.
I’ve only done sweetspot and threshold rides and was wondering if i should do some actual long rides?
I’m not really a racer, I just want to climb a specific mountain in the summer when I go to europe.
I’ve been doing just that. I decided to try ramping up my TSS after reading about what some of the pros do. An example is Megan Guarnier. Case Study on Megan Guarnier: The Making of a World Tour Champion | TrainingPeaks Her peak power increased as TSS increased.
So I went from ~400TSS to over ~600TSS and it does work. Its hard to ride 2-3hours on a trainer, but I have the time and, since I don’t race, and just like to do a lot of outdoor climbing, I do these long trainer rides at lower cadences with my front wheel elevated to simulate the angle of around 6-8%. I also started to customized my own workouts with the TR Workout Creator.
Incidentally, I believe that big gear training is key to climbing faster.
Hey Chris!
If you have the time and desire to get some long rides in your legs, then you can absolutely swap out some of the Sweet Spot weekend rides for long endurance rides sourced from the Traditional Base Plan 
That being said, I would recommend not skipping the Over-Under workout that is typically scheduled for Saturday. This is a highly productive workout that will really help you to get faster. If you can move the Over-under workout to a different part of the week, then you can go for long rides on the weekend and get the best of both worlds 
Best of luck with your training!
Adding volume is generally a good thing, as long as your body can handle the TSS. The benefit of adding volume at endurance pace is that the TSS is low, while you still get the benefits of improving your aerobic base/fat metabolism.
One note: to get the most benefits from endurance rides, they are ideally long (greater than 2 hours) or fasted. This is to get the most benefit from training your body to use fat as fuel.
I’m currently in my base phase following (generally) a polarized approach. Next month, I plan to begin SSBLV2 plan, and will augment this with long outside rides at endurance pace. So similar to the approach you are thinking of.