TR plans (e.g. SSB LV and TB LV) are designed with you having a goal event on the calendar in somewhat near term (e.g 20-30weeks). However, the predicament you are in regarding your Nov event being cancelled is similar to many of us. [For example, given likely vaccination timeframe, I am expecting my next target event to be in Q3’21].
If you take a higher level view of your situation, during Base Period, regardless of its length (e.g 12-20weeks), what you are primarily trying to build are 2 of the 6 skills described by Joe Friel in “The Cyclist Training Bible” - aerobic endurance and muscular endurance. Neither SSB or TB optimizes both. However, given your likely longer time horizon than in the SSB/TB plans you can develop both with a combination of both types training inherent in SSB and TB (i.e. you choose which workouts to do/not do and/or develop your own if you are so inclined). And you can manage the growth by tracking your CTL and TiZ (Time-in-Zone)) provided you have the tools to do so (e.g. Training Peaks Premium and/or WKO). Note: This can also be done manually with a spreadsheet, it just takes a bit more work.