We always try to get to Hahndorf at least twice a year, usually just before Christmas to see all the gorgeous decorations (trying to forget the 40degree heat!) and usually sometime in the autumn or winter.
We always try and eat at the Hahndorf Inn. It is always busy but considering that the service is always really good. We have our favourites in terms of food, but I am always amazed at the huge servings! They are a favourite amongst the many tourists as well, with the Japanese often sharing a plate amongst two of them. The prices are no more expensive than any pub. The beer is wonderful, even for a non beer drinker.
As I said, it is always busy, and therefore a little crowded. This would be my only criticism. A play room for the kids is a bonus. Try and go in the cooler months as they have a beautiful wood fire in one half of the restaurant. Outside dining is also an option.