Hints of viewing game at the Ark
Find the ground-level, open-air viewing bunker. The door ("Photo Hide") is located around the corner from the Gift Shop. Drop by periodically, especially if you see something interesting coming into the glade. This is a good place to feel in contact with the animals (smells, sounds, proximity).
Regularly walk out along the catwalk. It is a great place for birds. Before dusk look below the catwalk for suni (or even bush pig).
Just after sunset, check out the bird-feeder (along the catwalk). Sometimes galagos drop by. To encourage them, put out some bread (or pilfered goodies from tea time). You may need the hunter's permission to go out there after dark.
Also after dark (and particularly just before dawn?), watch along the base of the building for genets and mongooses. They may be foraging for the insects drawn by the floodlights. These sometimes come up to the side veranda looking for scraps.
Explore the ark: there are lots of interesting places on all floors.
Talk with the resident naturalist ("hunter"), or better yet, the staff member assigned the task of the all-night game watch.
The Aberdare salient is now open to the public. I suggest doing a game drive through the salient in the morning, before returning to the ACC for lunch. Alternatively, you can try to arrange with the Ark to drive up throughout the salient in the afternoon, and park there (they may not allow this). Try to get a map so you do not get lost.