I am following the training plan for almost 3 months now and I should peak after ~4 months. My Alpine objective at the moment is not very demanding (2.4km ascent over 2 days, easy hiking with one axe and crampons, no technical stuff, no super-heavy packs) and I wanted to use my fitness to do a half-marathon (or full) race. I am aiming at finishing the race in a reasonable time for a beginner (<2h for the half marathon).
This made me wonder how well would TFNA training transfer to trail-marathons and similar events if I would do all of the training without a backpack/added weight? I really enjoy the training so far and am seeing good results, but I am not sure how should I train for an event such as this https://www.lakedistrictskytrails.com/scafell-sky-race-40km-2900m (40km over 3km ascent). Is TFNA suited for this or is it suited mainly at mountaineering/alpine objectives where heavy packs are involved?