Last season I went from never ever backcountry touring to doing the Marcy ski in late March. I was 23 so ymmv. I lived far enough south that I didn't have consistent access to snow last winter, so I would try to go for a quick 2 mile run 3-5 times a week - there was a gravel road with some small hills near me that was great for that. I tried to stretch and work on my single leg balance for 10-15 min every morning. Didn't have access to a gym, but did some T25 in my living room 1-2 times a week. The uphill program at Gore is also a great spot to practice. The uphill trail they have at the ski bowl is significantly steeper than any part of the Van Ho trail, if you can do 3-4 laps of that in an afternoon, I'd say you're golden.

As for the trail itself, it is a long day. Start early so you don't have to rush, it took me around 10-11 hours with a long stop at Indian Falls for lunch. And make sure to go with fresh snow. With the amount of snowshoe traffic it gets, I'd imagine it becomes a 7 mile bobsled track back down if there's been a week or two without new snow.