[EN] Advice for my upcoming Austrian road trip?

I am remaking this post according to the standards of the moderators, sorry for my previous post not abiding by Rule 3.

Good evening people of Austria! I am in need of the advice of locals.

In short, I am coming to visit and hopefully propose to my gf there.
When? August 31st - September 10th.
Where? We land in Vienna, and immediately head to Upper Austria. from there we plan to drive around as follows and stay in Bad Goisern, Salzburg, Kaprun, and Klagenfurt before returning to Vienna and back home. So far this is what I came up with:

Currently planned route.

I have 2 questions, and any answer would be appreciated:

1) The cross-country routes from Vienna to Bad Goisern, and from Klagenfurt to Vienna - are these routes good for scenic views? I only routed maps through Gföhl and Freistadt because I think I want to take the B38 instead of the Autobahn.

2) What are some nice places to propose? Somewhere scenic and dramatic, if possible.

Any other recommendations highly appreciated. I currently don't know German yet, but I am trying to learn at least the basics on Duolingo, which I know won't be enough but it is all I have at the moment. Thanks in advance!