FWIW, here are my answers. If I’m doing it wrong, hopefully others will correct me! 🙂
“I suppose I’m curious how fellow endurance/climber people approach building an annual plan.”
My approach was to use TFNA and stretch out the Muscular Endurance phase of the Base Period (as the book says gains from Max Strength tend to plateau after around eight weeks, it didn’t make sense to extend that phase). After factoring in some trips and knowing that I will likely miss a week or two over the course of the year due to illness (commute and office work are great for picking up colds), my plan roughly covers the full year.
“How long do ya’ll enjoy that honeymoon period before you get back to work?”
Over the last two years, I took about two to three weeks off after what was, for me, a big trip in the winter.
“Is there such as thing as an off-season?”
I guess this depends in part on the sport. There are two ski seasons a year and if I were planning a trip to Chile/Argentina during the northern hemisphere summer, I would try to structure my training to take that into account. As to switching sports – hiking in the spring/summer/fall for me and snowboarding in the winter (both of them if possible!).
HTH.