Travel suggestions in Austria

Looks like best is to go Cesky Krumlov to Melk and then on to Hallstatt. You pass Melk on the way to Hallstatt. Its a very slow and round about way by train.

Assuming you're heading west after Hallstatt, Sam is right that it'd make more sense to hit Melk on the way to Hallstatt. You don't exactly pass Melk on the route to Hallstatt; when you get to Linz you have to turn east and go about 60 miles to get to Melk, and then backtrack west and eventually south to Hallstatt. If you're headed east after Hallstatt, for example to Vienna, just go straight to Hallstatt from CK. Then, on your way east you'll go right past Melk. The upside is that driving in that area is easy. The roads are excellent, as they typically are throughout Austria.