8 or 12 weeks plan

Hello,

My partner and I are planning to ski Mt Baker in 13 weeks and are wondering whether we would be best with a 8- or 12-week mountaineering training plan. If we go with the 8-week plan, should we do a 4 weeks transition beforehand?

Currently, we are running 2 to 3 times per week (45 min on average), we are doing a half-day of backcountry skiing per week, and we are doing one strength training per week. So, I believe our base is not too bad, but we are worried with the 800 meters D+ approach with a 45 lb backpack. We are currently skiing with a 20 to 30 lb backpack.

Also, what do these two programs represent in terms of days of training and number of hours of training per week? Will we be able to continue our half- or full-day of skiing?

Finally, should I just finish reading the book and organize us a training plan? Is our current training not too bad?

Thank you!