Training Recommendation? Stoneman-optimized

Looking for training program recommendations.

I use zwift for off-season training for mountain biking in Germany. Last year I rode my first Stoneman (2 days, 180km, 4400m climbing). Zwift worked great keeping me in shape through the Winter, and I would like to do another Stoneman next year.

I am wondering if the zwift pros here could recommend programs that optimize me for multi-day, longer, rocky climbs.

Thanks in advance.