Vienna's most important sights are all close by!
Distance Stadtnest – City Centre / St. Stephan’s Square about 1.7km, distance Stadtnest – Schönbrunn Palace about 3km.
Two different subway/underground lines (U-Bahn) are just five minutes walking distance from Stadtnest accommodation: U3 / "Westbahnhof" (or "Zieglergasse") in direction of the city centre / St. Stephan's Cathedral (4 stops, about 8min), U6 / "Westbahnhof" - with connection to U4 in direction of Schloss Schoenbrunn (3 stops, 1 x change, about 10min). Vienna's "Westbahnhof" (West Train Station) is only 8min walking distance from the Stadtnest. At "Westbahnhof" you can also catch tram/streetcar No 58 to "Schoenbrunn".
Location of the Apartments

Map of the Apartment's direct neighbourhood
West Train Station (Westbahnhof) - Stadtnest Apartment on Google Maps
Underground / Subway map of Vienna
Directions to Stadtnest Apartments (by train, by car, from the airport)
What else you should know in terms of location:
One of Vienna's biggest shopping streets, the Mariahilfer Straße, with many shops, diners, coffee houses, a big cinema (English version films) is basically next door to the Stadtnest B&B and holiday apartments.
Important museums (Museumsquartier MQ, Secession, Museum of Fine Arts, Natural History Museum) can easily be reached by underground/subway within minutes. The MQ can also be reached on foot in about 10-15min.
Supermarkets, banks (with ATM), pharmacies, post office, etc. are in easy walking distance.
The central location of Stadtnest private accommodation makes it easy to call a taxi at any time of the day.