A dilemma for Austrian GP

We do have a dilemma with me and my friends about where to stay and how to go to Spielberg.

Our options are two

1) We stay in Vienna and we take a train to the nearest station ( I am not sure if it's Spielberg or not ) , I would like to ask , how fast is the train and which one should we take? I noticed on some websites and on Google maps it either says 10h or 2h - 3h . Is it worth it ? Will we find a moment where the railways are under construction?

2) we find a hotel/airbnb in Graz , however we do know our only transportation is either a shuttle bus or rent a car , which one is more worth it?

That's the dilemma we have , I am pretty worried about the first take. Due to the fact I am not sure if the trains will be frequent or we will be on time to the sessions