I succeed to melt sugar and I didn't even destroyed our frying pan! :D (First you melt sugar, then you dip house pieces in melted sugar, and when you have done everything, you put the frying pan under running, hot water till all of sugar is gone.)
I decorated houses with icing. This is an easy recipe:
1 egg white
Just whip white and sugar together till mixture is sticky. Pipe decorations. The mixture stores about ~2 days in a fridge.
Here are the pictures: