I love this civ.
Frankly though, she is still too powerful in a humans hands.
I just played through GOTM50 with her, and went a route i was very happy with, though not the best way for absolute best times.
Tradition to get your core cities nice and tall.
Patronage for the extra gold influence and higher resting point (pledge to protect every CS = all are friends), and if you don't go Rationalism, the +science from CSes is nice too.
Commerce all the way down the right side. Protectionism's happiness is extremely nice.
If you decide to finish Commerce later and puppet lots of cities and trading post them, you'll be swimming in gpt.
I also opened Freedom for the +25% great person boost which i think works well with Coffeehouses, and buying great artists with faith for golden ages.
As for marrying CSes, i actually prefer to utilize this feature sooner than later, as you get nice already established cities with good buildings already built for not much more than 500 gold, which can be saved up very early. Considering a settler costs 500g, why bother?
It's
much stronger to just acquire CSes nearby to build your empire.
Just make sure the CS actually has some happiness lux along with it so it's not such a big happiness hit, and you'll have a crazy nice empire in no time.
After GOTM50, i think Austria actually works well for diplo wins too, as you don't need to marry every single CS.
You marry the good ones that have resources/luxs/locations that are ideal for you, and you keep the rest as allies to win via diplo later.
Of course you could also go the route of science, culture (only puppet the CSes, though TBH i don't think this is as optimal for Austria), or use them as launchpads to other continents, etc, for domination.
She's a very strong civ overall.
My GOTM post on her; don't read if you haven't finished or plan to play GOTM50
http://forums.civfanatics.com/showpost.php?p=12100742&postcount=27