Will be there in mid-September for a couple of nights. Suggestions welcome.
What exactly are you looking for? In old town? By the train station? Modest? fancy? We stayed at a very modest place near the train station that we were very happy with. The breakfast was excellent, it was a family run inn. Our room and bathroom were huge. Hotel Hohenstaffen
I should have been more specific. Comfortable, not fancy and near the train station is perfect! I will follow up with your suggestion.
Stay at Flockner B & B. Very close to the train station/bus station. Martin, the owner, is wonderful. This place opened only one year ago and everything is new. The room lighting is excellent. Terrific breakfast with eggs cooked to order.
There are two threads for this question. The other one is at https://community.ricksteves.com/travel-forum/austria/where-to-stay-in-salzburg-and-berchtegaden
There are answers there.
I stayed at Motel One Salzburg-Mirabell in May 2018. My sister stayed there May 2019. Decent sized comfortable rooms and good breakfast. Easy walk from the train station, about 5 mins walk from Schloss Mirabell, 15-20 walk to the centre of the old town.
I'd recommend something like
MEININGER Hotel Salzburg City Center or Pension Jahn I used to stay in two of these, pretty affordable in comparison with the other variants.