How are the roads from Gdansk? By the looks on Google it looks like not much of highway, and more of small roads and villages which should slow down the speed. Not very interesting in my mind (if it's true).
Yes, it`s true. Roads are mostly two-lane and through settlements. It is about 620 km, will take you about 10 hours.
I was told that it is better to drive from Swinoujscie. But from there I see two options, either to drive down on the polish side and connect to the A4 around Legnica
Yes, it is quite fast. From Świnoujscie to Legnica you can take the Polish S3 express way and then A4 highway. About 750 km. Also about 10 hours.
But there's also a way to drive down to Szczecin and then in to Germany and go to Berlin, and in Berlin make a right towards Cottbus and then connect to the A4 not long after crossing the border.
Going through Germany will also take you about 10 hours but the distance is 850 km.
So, as you can see, the time is the same.