Saalbach-Hinterglemm - just over an hour from Salzburg - has almost all of the things listed in @Fivemoreminutes1 Tyrol post either in the immediate area or nearby: A suspension bridge, a high-level climbing park and activity park, adventure/treasure hunt trails, an open-air pool, roller coasters at nearby Kaprun, Leogang and Saalfalden, cable cars, archery, numerous hiking trails in the mountains, cafes, mountain huts and playgrounds at the top of every lift and cable car, cake etc ... Stay in Tourist Office approved accommodation (B&B, hotel or apartment) and you get a Joker Card that gives free access to the cable cars, pool and many other activities.
Nearby Zell am See/Kaprun, 15km from Saalbach, has a breathtaking lake (with boat tours and rowing boats and pedalos to rent), a veteran steam train, a veteran car museum, and access to the stunning views from the Kitzsteinhorn glacier at 3,000m. See the post from @GetOffYourPhone for more activities in and around Zell.
Vienna, Hallstatt and Salzburg are sightseeing destinations, whereas getting into the mountains is all about actively doing stuff - hiking, climbing, biking etc.
For Austria in general, the Tourist Office websites (e.g. Saalbach.com) have a wealth of local information and usually also an accommodation booking service.