I expect to take 5-6 hours and have a couple of other Sportives before hand of similar lengths.
None of the workouts, outside endurance, or indoors are longer than 1:15, should there be longer ones ?
In the week leading up TR has scheduled VO2, Endurance, Threshold and Openers.
I’m sceptical, can anyone figure it out ?
I done plenty similar and off-road 80miles, and an accidental 108mile on-road.
Male, 63, shockingly low FTP which does respond to training.
I’d try the gran fondo plan, but I would also recommend adding in some actual outdoor rides of 3-4 hours once a month
TR wont schedule really long trainer rides because people simply don’t do them. But doing some longer weekend rides definitely won’t hurt.
Having said that I trained for london edinburgh london just fine using TR’s low volume plans, you dont necessarily need to be smashing long rides all the time. I just tried to do a 4hr ride most weekends and a longer ride once a month. For your purposes a longer ride once a month should be fine - it is more about comfort/fit, fuelling and pacing etc anyway past a certain amount of time.
I assume those ones in the run up to the event are a taper, shorter ones just to keep you firing but lower volume and TSS.
Agree with above, low volume plus a few longer rides and you should be A-OK.
Thank you both.
They hide the Gran Fondo well don’t they, but found it.
You might be thinking of the stock Gran Fodo Specialty phases, which are a bit buried in the Training Plans page.
What I’d recommend doing instead is adding your target event to your calendar and selecting Gran Fondo as the discipline. Then build out a custom training plan with Plan Builder based on that event. This will fill in the time between now and then with the best training we can that’s focused on the Gran Fondo discipline, which you won’t get from simply adding a stock Specialty phase template to your calendar.
Let me know if this helps and if you have any questions. 
Glad you found it.
I would agree with the previous post that following a Low Volume plan will get your legs ready for the ride BUT you need to do a monthly longer ride to get the rest of your body accustomed to it.