It is not quite possible to ski all the way from the top of the Zugspitze, at least not for me anyway. The ski resort is located about 300 m below the actual summit, but you can take a cable car from the Zugspitzplatt up to the summit, which we did at lunch time. The views were really interesting, as it becomes obvious that the Zugspitze is part of the first Alpine ridge. Looking North into Germany the landscape is practically flat, but if you look Southwards into Austria, you just see a ridge after ridge. Supposedly you can even see the Marmolada from the summit. We didn’t find it among all the peaks, though.
I want to go back to the Zugspitze in the summer. Although the summit is accessible by cable car (even several in fact) and in the summer tends to be overrun by tourists enjoying a beer at the highest beer garden in Germany, I think it would be nice to return. There are several hiking routes up, including a fairly difficult ascent via the (I hear beautiful) Höllental and its Klettersteig.