Didn't you mean Holstebro??
I can't find any place in Denmark called Hostelbro...
I have tried to search for train and bus travels from Amsterdam to Holstebro, and I think that the 200$ you save on flying to Amsterdam is not worth it....
A train trip from Schiphol, Amsterdam Airport, to Holstebro takes from 15 to 17 hours...
And you have to change train 3-7 times.
I can't get the price on the internet, but I would guess that you have to pay at least 100-150$ for a round trip to Amsterdam-Holstebro..
When are you planning to go to Denmark, and what are you going to do there? (If you don't mind me asking....

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