I’m 51 and did my own variation of SSB HV 1&2 late last year and I’m currently repeating SSB HV2. I try to follow the workouts pretty close during the week and do a long ride on Saturday. Fri/Sun vary based on my schedule and how I’m feeling. I’ve had no issue meeting/exceeding the TSS targets, but that’s with some unstructured time in the mix. I can really feel the benefit and building fatigue of the tues/wed/thrus blocks. Tuesdays are a cake walk and by thursdays it takes some mental focus on those 2 hour sessions. I’m ready for an easy week after 5 weeks of SS, but it doesn’t leave me wrecked like 3 weeks of build. I’ve been averaging 700+TSS per week since may and I’m feeling pretty fresh.
I don’t think there is any better training for gravel events where you have to put out decent power for long periods.