Do you think it is appropriate for a 10yo? Are you in direct sun the whole time?
I'd love to hear more about the tour in general...
Let me give you a better answer about the contents of the Wild Africa Trek. I was heading out the door when I gave the earlier answer, and now I have some time.
10 year old? Absolutely. We will be bringing our grandson as soon as he is around 10.
Here is a brief run-down of the trek.
It starts with a hike off the paved trails in the Africa section of the park. You will see two animals up close...the hippos and the crocodiles. For this section of the trek, you will be strapped into a harness, much like the harness for a zip-line. You will be locked into the harness whenever you do anything dangerous. You will walk over a Disney-rickety (which is to say strong) rope bridge, while looking down at the crocodiles and hippos. You will also be strapped into the harness as you peer off the side of a rock (with no railing) to see the hippos and crocs up close.
For the next part of the trek, you will take off the harness and get into a truck. You will see the same animals as the Kilamanjaro safaris, but you will have longer with each animal, and you will learn a lot more about them. And there is plenty of time for pictures (but you don't have to take them yourself). While the Safari ride gives you about 10-15 minutes on the Savannah, you will have about an hour to see everything.
Next you will go to a shaded platform that overlooks the Savannah and have lunch. They call it a snack, but for us, it was plenty of food to make our lunch. Here you can relax and look at the Savannah, particularly the elephants and gazelles. You can also see the rhinos and the lions from the back. They have binoculars for you. You can just chill out, eat lunch / snack, and enjoy the animals. There are restrooms here, too.
Next you will get back on the truck and get closer to the rhinos, lions, and a few other animals. Then you head back to the starting point.
Another key feature of the Trek is the the Cast Members have DSLR cameras. They take pictures of you and your group at every portion of the Trek, as will as getting great pictures of the actual animals that you see that day on your trek. You will be given access to all their photos as part of the price of the trek. This is important because it is not really safe to bring your own camera. They will let you do it if you have it will tethered, but their cameras are so good, there is no need. I could post our pictures, but it would be like spoilers.
Any other questions just ask.