Richard:
Sorry to be slow getting back to you on this great question: You’re a guide right? It is so hard to make a training plan for a guide because their job is so physical. As you say: since these erratic and often high hour weeks are the norm for you then it is not going to derail your training program. But for folks like you it is much more of challenge to design a long term plan. If you’ve been doing this type of thing for a few years then your base aerobic fitness is already high. You will benefit from a special approach when you spice up your massive base with some specific workouts when you have time and energy. I write special plans for guides who have a goal but not much time/energy to train. Its tricky and has to be adapted to each person so I can’t give generalized comments in this kind of case.
Scott