how long are you staying for? going to innsbruck might not be the best idea due to distance, if you are short of time, there are many places around wolfgangsee which will take up a lot of your time.
mondsee is a reasonably nice small town, but with not a lot going on. the main attraction there is the chapel used in the SOM, but other than that, the lake shore is really all that there is to see. grossglockner is a great driving road but it is very weather reliant. no point going there on a bad day, so if you start out, you need a plan B.....possibly zell am see or kaprun.
you have to assess what you really want to see and do,
Thank you both, nakagoli & roefamilyuk for your advice. Will skip Innsbruk cause it looks very touristy & Mondsee too because of it's distance. Hallstatt & Grossglockner is on my list. Weather predicts thunderstorm & rain so I guess we should stick to plan B & take a coach trip to the glacier & bus / train / ferry combo to Hallstatt.Does that sound okay?
That plan certainly sounds good and saves the bother of a hire car,. Grossglockner is only worth the trip if the weather is good so check the forecast beforehand. No point in such a long day trip if there are no views