I use the 20 week Big Vert plan and pull the functional runner workout forward into an 8 week transition period. I consider the Functional a general strength workout, and find if I do it consistently through the transition and increase from body weight to weighted exercises with lower weight dumbbells (~10-20lbs) then I feel very ready for starting heavier work in the Base (gym or sport specific). I also do a shortened and modified version of the Big Vert plan for ski mountaineering, and post transition I add in a 8 week max strength gym workout. I feel very ready for that series following the functional runner workout as prep.
I also have slipped the functional runner workout as a mini-transition (~3 weeks) between by ~16 week ski Big Vert and the start of my running Big Vert just to make sure that my incremental ramp up of running is well supported. During this mini-transition I still do some runner ME gym workouts and some specific strength 8-10′ hill sprints and feel out how my running legs are doing. I do maintain some running throughout the ski phase too.