When you left the front entrance of the TDC compound, you went up to a road by the Keelung River.
Going left on that road took you toward the zoo, Chungshan N. Road, and the Keelung River Bridge.
Across the bridge to the right was the road to the 63 Club. Bear left instead, and you were on the road to Grass Mountain. If you look to the left of the bus on the bridge in this picture, you can see the driveway to the Grand Hotel.
This is a view from the bridge.
The Grass Mountain area is shrouded in clouds.
To see what this area looks like today, go to Google Earth and enter these coordinates: 25 4' 25.03"N, 121 31' 31.82"E. It is a different world today.