There are multiple ways to get to Upper Injisuthi Cave. The group I went with started at Injisuthi and walked up to Centenary Hut, where we camped the first night. Don't underestimate the first day. Heart break hill (the last 3km before Centenary Hut) really packs a punch. Centenary Hut is really run down and quite disgusting to stay in. In my opinion, you need to take a tent and camp outside. Water at Centenary Hut is also not the easiest to get to. There is a little spring 400m down a hill where you can collect water. The night we had at the Hut was the worst one I have had in the Drakensberg. The wind blow in gust of 80km an hour and there is no way to get out of it. All three tends we had with us broke that night ( the Hut is on a ridge and is very exposed ). I would seriously suggest staying away from Centenary Hut unless the weather is good.
The next day, we walked to the base of Corner Pass. This is a very challenging pass. Give yourself a good few hours to walk it. There is a easier pass (Judges pass) which is one valley over. Once at the top of the pass, it is about a 6km walk. Just because you at the top of the berg (Lesotho) don't think it is flat. There is still a long hill you walk up but the Cave is near so your spirits are high. The Cave is a very rewarding sight. It is set about 400m from the escarpment. People have built a rock wall which adds lots of protection from wind and rain. The Cave can comfortably sleep 8 but with a squeeze it can fit 12. Water is also abit of a problem. The nearest water source is 400m away at the escarpment. The views you get while getting water are absolutely amazing. You can look over the edge of the escarpment and see a 1000m drop. BE SAFE!!! In winter the Cave does get very very cold.
The next day, we walked via Mafadi to the top of Leslie's pass. It's an amazing walk along the escarpment. Leslie's Pass is a long pass which takes you into the Marble Baths valley. At the base of Leslie's it is about a 6km walk to Marble baths Cave. You can either spend the night at Marble baths Cave or you can push on (Like we did) and walk back to Injisuthi. It makes for a very long day 3 (25km) but at least you get to sleep in a warm bed.
Overall, Upper Injisuthi Cave is amazing. I seriously recommend it to everyone with abit of fitness. I would definitely suggest looking at the weather before staying in Centenary Hut because the winds can get very strong.