Go to the airport website:
Engadin Airport St. Moritz Airlines: News
They have webcams, good tool for checking the conditions before you fly, or during your flight if you have internet access in your airplane.
Fly slow; know your turning radii at your speeds. Plenty of videos on YouTube.
It is courageous to go to this airfield on an A320 if you've never been there before.
Maybe you want to bring in a local pilot from there and have him be your 3rd man in the cockpit? Or travel there and hire some small aircraft with local pilot and do a thorough recon flight!
(@ website: you'll see a pic of the Breitling Super Conny on the ramp.)