Agree with Classic Crew.
Get photos of Narsarsuaq or even better beg a big jet simulator demo of the approach. Respect the minima, mine were 20/20 blue and you had to have been there before. If it is 20/20 blue, take the scenic fiord route, it might just save you one day. Similar issues apply at Vagar, Reykjavik, Sondrestom, Iqualuit, and Gothab (last ditch).
Take a good survival kit; very useful during refuel and essential at some night stops.
Plan for and have available, options for all eventualities. Engine out, de-icing failure, pressurization failure, fuel feed problems, fuel leaks. Ensure that you have good and reliable comms. Listen out on 121.5; there is also a chat freq for relays via the big jets up above. Even the standard route is fatiguing, do not over stretch flight time, beware airfield closing times, and available daylight. Brush up on DR nav and plotting. Relax and enjoy the trip.