Liechtenstein is small enough that the rest of the country is essentially a series of day trips from Vaduz. Malbun, the only ski resort, is a 25-minute bus ride up into the mountains and is worth a half-day for the hiking in summer and the runs in winter. The mountain village of Triesenberg, halfway up the slope, has a small museum on the Walser people who settled this part of the Alps in the 13th century.
Across the border, Switzerland and Austria open up easily. The cathedral city of Chur, 40 minutes by train south, claims to be the oldest continuously inhabited town in Switzerland. Feldkirch in Austria, half an hour north, has a medieval old town and a hilltop castle. The Säntis massif and the Appenzell hills are an hour west by car or bus.