I'm removing the Uber "tip" as it seems most people aren't having any luck with it. I did all of these on I Am Death Incarnate difficulty and you probably should too.
This is a video of the Wulfburg Square Challenge Map in Wolfenstein: The Old Blood.
To obtain Gold, you must be playing on "I Am Death Incarnate" or "Uber" difficulty. The gold medal is rewarded at 17600. For higher scores go for headshots (600 points) and try to keep your combo active as you receive an extra 200 points for each kill in the combo.
For this challenge I stayed up top in the sniper tower located in the center of the area. Use the sniper to take out both of the Super soldiers and one of the Captains. After that, take your time and finish off the rest of the enemies in the area.
Make sure to not kill the second captain until after the second group of enemies have spawned.