The route to the Hluboka is very well marked from Ceske Budejovice which is about 8km to the south of Hluboka nad Vltavou, look for the signs that say zamek (chateau). But once we got to the city, we had a little trouble figuring out how to get to the chateau, some of the streets look like you're not supposed to drive on them and only authorized vehicles can park near the chateau. We ended up parking near the tourism office and walking up, the signs said we needed to pay to park but we didn't see a paybox. When we asked at the tourism office they said it was past the time that we needed to pay.
Hluboka nad Vltavou is a town in the South Bohemian Region of the Czech Republic, near Èeské Budìjovice. You can get there for example from Prague, by a direct bus, takes less than 4 hours. Direct buses aren´t that frequent, you can travel to Ceske Budejovice from Prague, it takes less than 3 hours and then you have to change the bus to get to Hluboka nad Vltavou. It takes 20 mins to get to the town from Ceske Budejovice.
If you travel from Cesky Krumlov (see my tips), go to Ceske Budejovice (45mins), then take another bus to Hluboka nad Vltavou (20mins).
You can rent a car, for example in Ceske Budejovice. You can´t park in front of the Castle but there is a parking site in the centre of the town, just follow the signs. You will have to walk up the hill, quite steep but it is definitely worth it. You will walk 5-10 mins, depends on how fast you walk.