I am currently in Vienna and will be for the next few months or at least I base my touring from there, the Vignette for Austria isn't bad 5Eur for 10 days get at most gas stations, but I will say this the interstates are not "fun" touring roads, they are a means to end at a destination, I took E45, E60, and S6 at different times to shorten distance to where I wanted to be but not once did I enjoy riding on it, high walls, lots of traffic, and overall it doesn't go near beautiful places. That being said when you exit the interstates, the roads are very windy and your time to destination jumps, 150mi is a 4-6 hour day ride in the Austria at best. speeds on country roads are max 100km so 50mph ish, most are 80km, and in the small towns 50km. So planning more that 150 a day or you will start to get behind and then forced to the ugly interstates.

I haven't witnessed enough around Vienna that would make me stay close to there, Beautiful city and surrounding countryside but not worth staying nearby IMO expect the city itself great pubs all over, anywho there are some great places a little over a day ride from there that are way better.

Berchtesgaden, Bavaria the little German tip that drops south of Salzburg is very beautiful and good alpine roads there, lots of Bavarian B&B's with small pubs but it's a sold 3hr hard ride to there from Vienna on interstate but a stop in Steyr Flusswandern is worth it.
Form there I'd head south, you can catch Grossglockner, the Zell am See to Zell am Ziller is a stunning road to ride, the Malta high alpine road, or Nockalmstrafbe is another road that gets down you into the beautiful Triglav national park where 2 weeks is barely enough to scratch the surface, any further west and you will be wasting all your time on ugly interstates. dop south to the area around Trieste for that Med beach life before returning via Ljubiana and Maribor. That would though require you to be able to cross into Germany, Italy, Slovenia, and depending on which country you got the bike Hungary and Austria too.

Another idea if getting the bike in Bratislava heading east towards Tatra Mountains, you will get the same Alpine feeling without leaving the country, stop for castles Bojnice Castle something out of a movie!, Orava Castle, and Spis all stunning, Hiking Súľov Rocks, Dobšinská Ice Cave, and around Tatra. all same country and definitely plenty to do on a 1-week schedule, great people, great pubs, and you could get a very good price compared to Austria.

So much in every direction from Vienna its why I base there, but just remember Highways suck and have 0 enjoyment, but off of them it takes forever to get somewhere so know that going into it.

Don't forget! Your riding in a different country so even a crap road is more than some will ever get to see, so have fun!