Cross country ski holidays

I can only comment on Austria. Depends what the family needs in terms of pistes (if you mean quiet and with stuff for kids, or a big resort to keep late teens amused). In Austria two of my favourite small to medium sized family-friendly resorts do a lot of Langlauf (though I have only found time to try it briefly - and it does take some re-learning of co-ordination, you will need a couple of lessons). Those resorts are Seefeld (which I know well - advertises 170km of Langlauf tracks I seem to remember) and Galtür (which I just discovered). You could also look at the recently extended Alpbach for a larger number of lifts, combined with plenty of Langlauf tracks.