Smack in the middle of a citrus-growing and horse-breeding area, Addo Elephant National Park is home to elephants, buffalo, black rhino, leopards, hippos, spotted hyena, hundreds of kudu and other antelopes, and lions. At present the park has about 420,000 acres, but it's expanding all the time and is intended to reach a total of about 600,000 acres. But Addo is a work in progress: not all of the land is contiguous, and parts of the land are not properly fenced in yet.
The most accessible parts of the park are the original, main section and the Colchester, Kabouga, Woody Cape, and Zuurberg sections. The original section of Addo still holds most of the game and is served by Addo Main Camp. The Colchester section, in the south, which has one SANParks camp, is contiguous with the main area but is not properly fenced yet so there's not much game there. The scenic Nyati section is separated from the main section by a road and railway line; there are two luxury lodges in the Nyati section, and the game-viewing is excellent (but exclusive to guests staying in the lodges). Just north of Nyati is the mountainous Zuurberg section, which doesn't have a large variety of game but is particularly scenic, with fabulous hiking trails and horse trails. It is also the closest section of the park to Addo Elephant Back Safaris.
You can explore the park in your own vehicle, in which case you need to heed the road signs that claim "dung beetles have right of way"... seriously. Addo is home to the almost-endemic and extremely rare flightless dung beetle, which can often be seen rolling its unusual incubator across the roads. Watch out for them (they're only about 2 inches long, but they have the right-of-way—as well as sharp spines that can puncture tires), and watch them: they're fascinating.
Instead of driving you could take a night or day game drive with a park ranger in an open vehicle from the main camp. A more adventurous option is to ride a horse among the elephants. Warning: no citrus fruit may be brought into the park, as elephants find it irresistible and can smell it for miles.
Addo Elephant National Park, South Africa