In reply to Sealwife:
Deffo do a night in a mountain hut somewhere, it'll be a great adventure/experience for the kids. If you book in advance during the week you'll probably get a family room and avoid the potential unpleasantness of a crowded dorm. I've not done much in Austria, but this is what I have done (as day trips):-
Mittenwalder Hohenweg VF - technically easy and not particularly dangerous, but a spectacular ridge. Easy access via cablecar, then more or less downhill all the way. The descent to the Brunnstein hut is a bit hard on the knees, but you can have a nice beer or coffee at the hut. You may see Chamois / Ibex if you're lucky like we did.
Lachenspitz kletterstieg - a modern, safe mid-grade VF. We took the Vogelbahn cablecar up and walked a reasonable way to get to it. Great views from the top and there's a big hut at the bottom by the lake (Landsberger Hutte). Lots of paragliders by the Vogelbahn. Don't do the descent to the NE from the Lachenspitze - it's gravelly and unpleasant/dangerous, go down the 'tourist path' to the SE.
I like the idea of doing the VF around the Drachensee / Cobourger hutte and have an overnight plan for doing those.