Go off the autobahn at "Pians-Paznaun" and drive in the valley, pass Ischgl until you reach Mathon (ca. 24km from Pians). Go right just before the church and immediatly your are in front of Haus Thomas.
During the winter, please do not use the Silvretta Hochalpenstraße since it is closed, please drive via Pians!
Please don't forget to buy a vignette since this is obligatory on Austrias autobahn! It can be very snowy, so use snow tyres and bring snow chains with you for any cases..
If you travel by train the train station is called Landeck-Zams. You can go by bus (1 hour drive) or by Taxi to Haus Thomas.