@GHetherington, you took the words from my mouth.
I’m a 54 year old TT-ist in my second winter of TR.
My observations on the subject are as follows.
Hit it hard, ride the threshold and VO2 workouts until you can’t go any harder. Make yourself suffer, deeply at times. You WILL get gains.
Ignore the small issue that you have done a few more laps of the sun than other riders. It’s completely irrelevant to me.
Listen to your body. One advantage we have is that we’ve had a good few years of listening to our bodies. Rest and recovery is good. Sometimes a little extra is better. Sometimes less.
Be flexible in your TR plan. The OP structure sounds good but it may be overcautious and restrictive at times, in that you may miss out opportunities for improvement at those times when you don’t really need the extra recovery week.
My approach is to do low volume plans (currently SSBII low volume) which allow the opportunity to either move the next workout back a day to give an extra day of recovery or insert an additional workout as and when my body tells me it’s appropriate.
Last winter using this method I went from 242 to 275 FTP at 70kg.
Good luck with your training all of you, whatever number you are!