Hotels with family with 3 teens

Have you searched apartments? Even if you want to avoid AirBNB and VRBO type situations, there are usually some local companies that handle rentals. I always go to Booking.com first, then branch out from there.
Having the opportunity to make your own breakfast/snacks and do laundry are major pluses for renting an apartment--with a family of five I thinks it's best.

I'm a solo traveler with no personal recommendations for you, but you might try booking.com. It has listings for apartments as well as hotels and B&Bs. Occasionally hostels crop up as well. Some of those have family rooms with multiple beds and a private bathroom. Hostel furnishings are pretty bare-bones, but your teenagers might enjoy the social aspects, and staying at one hostel could balance the higher cost of two hotel rooms elsewhere.

There are a few websites with hostel listings. I haven't used them, but Google will probably turn them up. I think HostelWorld is one of them.

In many countries in Europe, the number of people allowed in a room is governed by regulations, so its not just a matter of sliding another bed or cot into the room. Its a matter of taxes and safety codes, so its not surprising to find limited numbers of hotels with rooms set aside for families

In Salzburg Das Grune Hotel has rooms for 5 people. My daughter's family stayed there and liked it. Also Hotel Drei Kreuz has rooms for 5 people in Salzburg. You can look at them on Tripadvisor.com or booking.com or hotels.com.

Try this website for holiday appartments (often cheaper than AirBnB and VRBO)

https://www.fewo-direkt.de/

Site is only available in German and French

Meininger Hotels are group and family oriented. Also in Munich and Salzburg located.

Official German DJH hostel in Berchtesgaden with family accommodations:

https://www.jugendherberge.de/en/youth-hostels/berchtesgaden/

Fantastic you are taking the teens to Germany! Try searching for aparthhotels (apartment hotels). Adagio is one brand we have used. They usually have a kitchen/dining area and more than one sleeping area. Additionally, they generally have a staffed 24-hour front desk like any other hotel. The downside is they don't always provide breakfast, something I always look forward to in Germany. In a standard hotel, you will likely need multiple rooms. Good Luck with your search.

In the Salzkammergut, I think Rick stayed here in Werfenweng in his old videos: http://www.kendlhof.com/index.php Not sure of public transportation, but it was in his good old days, so probably a bus or access to a train? It's a FEWO, so you would have to provide your own food. Maybe bread service and fresh eggs in the morning? Get a deal on two FEWO?

Where do you want to base for your hikes and for how many days?

I think a five person room might be a little hard to find and crowded with 5 people, but you might find one with breakfast (a lot of Germanic hotels include breakfast with the room).

Your other option would be a Ferienwohnung (vacation appartment), but these often want more days than a simple room. Most FeWo are larger and have several sleeping rooms, although part of the sleeping accommodations would probably be a sofa bed in the living room.

The advantage of a FeWo is that there is a kitchen in the apartment so you can fix your own breakfast, have coffee before you have to go out). The disadvantage is that groceries for breakfast are not included. You have to get the groceries at a store. Make sure there is one nearby (unless you have a car).

I've stayed twice in FeWos, once for seven nights, once for 9 nights. In both I had to go out and stock the kitchen - coffee, creamer, sugar, rolls, butter, cold cuts, cheese, marmalade (the German word for any preserves), eggs, etc. I don't think having my own kitchen saved me money. I left half of the kitchen supplies that I had bought there when I left.

Another thing to consider is that FeWo renters are often older people and not so likely to speak English. How's your German?

Look at apartments. Here is where I stayed just outside Salzburg, near the light rail.

www.neuwirtgut.at

You could also consider a farm stay near Salzburg--better for hiking, getting to know more of the regional culture, you get familiar with the village and such.

When I was a child we stayed on a farm in Maria Alm--a bit further away, but great hiking, we loved playing with the family's children (it was 1990, so we reenacted the world cup in the cow pasture many afternoons--Germany vs Austria). We did a day trip to Salzburg to see the town and to the Salzbergwerk and even took the host's two oldest, who were our age, with us. Of course, we all spoke German. But we loved being on the farm, loved walking down the hill and feeling like we were familiar with the town and where to eat, loved getting to know the family, had great hiking, and so on. I don't know what it cost or what it was called, but those options might be good.

In addition to Booking you can simply look at Google maps. This is a go-to for us. Most places are listed on multiple sites, but you can get great impressions there and get a good idea of distances, etc.