Grand fondo multi day event

June next year in for 3 day event, daily routes 150km and 3000m climb. My intention is to be at best for this event and start training now. Currently I am on continuous with xert. TP 265w/LT 217w. 65 years, 77kgs, 182cm ride 12 to 15000km year. I can fit 12/13 hours weekly into ridging most weeks. What would the recommended program and rate be to reach peak at event?

Thank you