Ok well Åre is brilliant if you get the snow. It is Steep and exposed to high winds , so it can be icy and challenging when those steep slopes get their snow blow away. However there are a lot of tree runs and when it is good it really is fantastic. very quiet and real feeling of being in the middle of nowhere.
Trysil, I must admit, I have not yet been to. I am going at the end of February so can confirm more then, but from speaking to friends the area is fairly large, but it is not particularly steep. The top of the mountain is featureless. It sounds good for a week and I have been to Sälen , the resort in the same area but on the Swedish side pf the border, which was Very family friendly but not challenging. I think Trysil will be more of the same, decent resort, good fun, quiet, good snow, but not a massive steep area where you never do the same thing twice. Also a pint will be 9 quid so bring booze.
Where are you traveling from ?