Family of 4 - Northern Italy, Switzerland, Austria itinerary suggestions in August!

Why Innsbruck? Personally, I’d fly from Zurich to Vienna. Or I’d go somewhere a bit more quaint.

I wouldn't stay in Interlaken. Its basically a transportation hub. Stay in the mountains even if only for two nights. Its beautiful there. Our family of five stayed at Chalet Fontana in Murren. They may not have space but have a look at other spots in Murren or Wengen if not. Other options are Lauterbrunnen or Grindelwald. I'd opt for any of those locations over Interlaken.

After visiting Lucerne and the Jungfrau region i wouldn't bother with stopping in Bern.

It looks like you wanted a trip to the Alps in Italy and Switzerland but are flyin into Milan to save money. Fine. Going to Varenna is great, it's nice there, and spending two nights gives you a whole day. You can cross the lake to Mannaggio onnthe ferry and rent kayaks or swim (the water is cleaner than at Varenna where there are too many ducks and swans).

Then you ride the train on the scenic Bernina Pass route into Switzerland. Also good! But from here your itinerary is way too heavy on trains. Basically you are spending all of your four days in Switzerland on trains. That is expensive and not the best way to enjoy Switzerland.

Then you head to Innsbruck (why?) and on to Vienna, which is a long journey. Look at a map and check the train times. And prices. I haven't been to Vienna but wonder what there is you want to see there to justify going so far, when you have to come back to Milan to fly home.

I would suggest you add days to your time in the Berner Oberland and don't stay in Interlaken. Stay in Lauterbrunnen or Mürren or Gimmelwald. Then if you want to see Austria maybe go to Salzburg, and Munich instead of Vienna if you want a big city experience.

I agree with the others above. Stay up in the mountains not Interlaken. Lots of great walks near Murren and Wengen. Skip Vienna, I was there last summer. It is a lot of travel for such a small amount of time visiting. It is worth more time. Your trip is very rushed. Slow down. Do you have tickets for the Last Supper? I thought the reservations sold out very early. Perhaps travel over to Montreux and take the Chocolate Train to visit a chocolate factory. What kid does not like chocolate?

I agree about not staying in Interlaken. We stayed in Wengen last March. Beautiful! Took a day trip to Interlaken. Both agreed that we were glad we chose Wengen. Interlaken just seemed so "touristy" and lacked the charm of Wengen.

Enjoy!

Dropping Innsbruck and Vienna will save you money and add to your enjoyment.

As others have mentioned , stay up in the valley or mountains, not Interlaken. You have 13 nights so consider this

2 nights Milano
2 or 3 nights Varenna
3 nights Luzern
4 or 5 nights Muerren or Lauterbrunnen (yes, it is that good!)
1 night Milano before flight

Depending on arrival time you could actually go right from the airport to Varenna then put all of your Milan nights at the end saving one hotel change.

Putting in one more vote for what others have suggested - stay in mountains in Switzerland, not Interlaken. Spend more days there and skip Innsbruck. We spent one night in Innsbruck a few years ago, when we'd flown into Munich and were headed to Venice on the day (a nice scenic train ride, by the way) and we enjoyed it. But once you're in the Swiss Alps, you're already seeing better scenery.

I had my sights on varenna for a long time but my husband found a good deal in Bellagio. I was so glad he did. We enjoyed Bellagio very much and had a bit more going on than Varenna (which is precisely why some prefer it). There was a beautiful walk up and over the back side of the town. Wonderful