As you move, there is a great deal of data available. Even with the unexpected change in route and Sandrea's injury, the typical caravan of its followers has diverted with it, both animal and human, creating a long tail behind Sandrea. This makes a range of scannable data available. For example, several of the human followers carry banners that are roughly speaking written in Chinese (a modified script, minor differences) announcing themselves as the sea coast people who follow Sandrea (their version of Sandrea is "Earth-shaking Gardener" which can be easily enough inferred). Their equipment is primarily pulled by beasts of burden, creatures you would primarily recognize as oxen albeit with several modifications including toughened hide with metallic elements and greater muscle mass. The equipment is primarily carrying apparatus for agriculture as well as survival gear, foodstuffs, and some weaponry. Similarly, the forests around Sandrea indicate the presence of both herbivore and carnivore beasts, with movements indicative of historical big cats briefly flashing in and out of sensors as the most present danger should you behave in a manner indicative of threat or prey. 

Which brings us to the task. To climb Sandrea is an achievable task. The first and in some ways most difficult task is actually approaching Sandrea. The forests around her are patrolled by the hunting cats that look for prey that follows in her wake and the area behind her is full of people who might notice and question you (particularly if you were, say, to attempt to barter or steal useful climbing gear from them). 

The second is to begin the ascent. If you do not pierce her skin, she would not even notice you mounting her legs, but the legs are in some ways the most difficult part of the climb since they have no particular handholds and are far to wide to shimmy around. A typical human climber would evaluate this as requiring the creation of some kind of perch or the use of rope attached higher up. 

Third, once you clear the legs, the mass of vines and foliage becomes an aid to you, and navigating the back is a matter of not becoming bogged down in damp soil and dense, shifting foliage. Or accidentally getting caught in a landslide as soil drifts from Sandrea's back during her steps. 

Finally, to clear the neck and reach the head is somewhat precarious because of the risk of her movements, but her neck is generally held at an angle so the actual slop is not terribly bad. Really just a matter of how you prepare yourself not to have the whole climbed spoiled at the last second should she unexpected look to the side or change her path and move her neck such as to throw you off.