A bit late, but here goes:
Driving is not such a bad idea as the distances are relatively short. The train is also rather expensive, so costs for driving wll not be so high. Driving the alps is rather scenic, and I actually prefer it to the train (note:I live in Austria and do this a lot). It really depends on the weather, which is expected to be a bit warm (in Austria).
As for the itinerary, Hallstatt is a rather great place to visit, although I have only been there in summer. There is good hiking and it is really an idyllic mountain village. 2 days might be more than needed in winter. If OP skis, then the Salzkammergut is a great area for this and there are lots of winter activities IF he has the proper attire. If not, Salzburg is really close and can be done as a day trip if needed. I imagine that there is enough to occupy OP for 2 days. For restaurants, the village is small and there was not too much to chose from. Most of the better places were down by the lakefront.
As stated earlier, the bigger cities would make more sense. Vienna is worth 3 days, especially with the Christmas markets. Lots to see and do in December. Prague is doable in 2 days and I am sure OP can manage an extra day if his/her schedule changes.
Just saw the routings offered by allset2travel, and they are good ideas. Just check the weather first as driving in bad weather is not recommened, even on the Autobahns. If the weather is good, then these suggestions are good.
One last thing, there were recently several posts by abhilfe (?) about a similar itinerary, including Hallstatt. Could be worth a PM!
Last edited by livious; Dec 12, 2010 at 12:27 am