With respect to your main question, this older podcast from when 2020 took a nose dive and events were canceling across the board, might be helpful in light of your question (if you haven’t checked it already).
- Training Without Events, Outside Workouts, Hormonal Birth Control and More – Ask a Cycling Coach 251
Outside of that, I’d suggest trying Plan Builder with your event added to the calendar, and see what it gives you. The essence of prior TR suggestions (Base, Build, Repeat vs Specialty) are largely captured in there, and might give you what makes sense. If you don’t like it, you can do a manual plan of your own choosing.
Those are just a couple of options that are accessible now. Hopefully TR can address the question if those don’t meet your needs.