Sorry, James, I think it would be extremely illuminating to find out when, where and how he skis on his own turf in the Alps. I concede the point that he had an extremely rigid plan on the U.S trip and would not deviate come hell or high water, and further inquires about this specific trip might not reveal more than we already know.
So start off with the basics.
1) Where did he grow up and learn to ski?
2) Where does he live now, and what are his "home" areas that he can ski via daytrip? What are his favorites among those?
3) What are his favorite major resorts in the Alps, and does he take weekend or longer overnight trips regularly to any of those?
4) Alpinfans website shows him skiing lot in late December to January and in March. Does he avoid February due to job responsibilities or avoiding the school holidays? Or maybe he is skiing but we aren't seeing it on Alpinfans because it's not at first time areas.
5) Was he really skiing only ~25 days a season 2003-2014 or is that another misinterpretation because it's only counting new areas?
6) When did the "ski area collecting" project start?
7) Multiple areas in the Alps comes about naturally with so many lift interconnections. When did he start the method of skiing multiple areas in one day while having to drive between them?
1) Where did he grow up and learn to ski?
I grew up in Zürich. Every year we spent two weeks of ski holidays in Sörenberg, and during the first week I had to go to ski school. My father was in a ski club that owned a ski house with its own small lift, about an hour from Zürich, so we went there sometimes. Otherwise we did lots of weekend trips to the many small ski hills close to Zürich. Quite a few of those lifts unfortunately no longer exist.
2) Where does he live now, and what are his "home" areas that he can ski via daytrip? What are his favorites among those?
I still live in Zürich. Define “daytrip”

For me it usually means up to about 2 hours driving each way. Within that radius there are probably well over 200 ski areas. I have always wanted to analyze this properly: which city has the best “ski catchment area”. My guess: Geneva. Possibly better than Innsbruck, Grenoble, or Turin.
Some of the biggest areas we can reach within that time are Jungfrau, Engelberg, Andermatt, Laax, Davos, Arosa-Lenzerheide. In Austria: Damüls, Montafon, and Arlberg (depending on traffic and conditions). Smaller areas I really enjoy: Hoch-Ybrig, Flumserberg, Airolo, Meiringen-Hasliberg, Obersaxen, Grüsch Danusa.
3) What are his favorite major resorts in the Alps, and does he take weekend or longer overnight trips regularly to any of those?
My top favorites include Dolomiti Superski, Les 4 Vallées, Portes du Soleil, Sölden, Saalbach-Hinterglemm, and since 2016 also Arlberg. I also love Val d’Isère, La Clusaz, Chamonix, and Serre Chevalier.
I try to revisit these major destinations every few years. St. Moritz, Ischgl, and Zermatt also appear on my list fairly regularly.
But my absolute favorite is Scuol. That’s my second home. I worked there as a ski instructor, many close friends live there, my godson grows up there, and my family loves it as well. I try to be there two to three times each winter and another one or two times without skis. It’s a bit of a hidden gem right next to the Swiss National Park. Probably not the first place I would put on an international ski traveler’s bucket list – but home is where the heart is.
4) Alpinfans website shows him skiing a lot in late December to January and in March. Does he avoid February due to job responsibilities or avoiding the school holidays?
Thats correct. February is peak school-holiday season in Switzerland and therefore the most crowded and expensive time of the winter. In addition, the university semester starts in February, and several members of my team have children and need to take vacation during that period. That makes it difficult for me to be away as well.
So I tend to prefer January and March, when conditions can be excellent and the slopes are generally less busy.
5) Was he really skiing only ~25 days a season 2003-2014 or is that another misinterpretation because it's only counting new areas?
I ski far too little. But fortunately, it wasn’t that bad (with two exceptions). In the early years of my blog, I used to publish seasonal statistics – it includes ski touring, I do not have that on Alpinfans, but on my blog
https://grandeboucle.blogspot.com/2018/06/jahresabrechnung-saison-20172018.html
6) When did the “ski area collecting” project start?
As I sad in the last post, strictly speaking, I don’t collect ski areas – I collect ski lifts. But that statistic is not officially tracked anywhere.
The first time I counted my lifts was in 2003, during après-ski in Kitzbühel. I was at around 750 lifts and set myself the goal of reaching 1,000.
After finishing my PhD, I rewarded myself with a trip through France’s largest ski areas, from the Mediterranean all the way to Chamonix. That “Grande Boucle” became the starting point of the blog and the more systematic tracking.
But the story actually begins much earlier – in 1975 in Sörenberg – when I wasn’t allowed to ride the lift next to mine because there were two separate lift companies with different tickets. On the same mountain. A small-scale version of Deer Valley–Park City.
7) Multiple areas in the Alps comes about naturally with so many lift interconnections. When did he start the method of skiing multiple areas in one day while having to drive between them?
I’m not entirely sure I understand the question – could you clarify what exactly you mean?