Nkosazana cave is pretty exposed (big front entrance) so wind, water and snow can get in fairly easily. However, in a bivvy or survival bag (cheapies are under R100 at CUM) you’d be fine.
I have no idea of your level of fitness or hiking experience, so my answer will assume you have at least an average level of fitness and experience (else you probably wouldn’t get to KBC from Moncs Cowl in a day).
Day 1 is therefore fairly easy going, about 16km’s or so, the main climb is to get up to the lower berg via the Sphinxs, then it’s fairly level until you eventually drop down to the river for the final 2,5km’s to KBC. This section can be quite tough - you’ve already done a bit of climbing, put some milage on your legs and typically this section, when done later in the day is quite hot as well. However, it is the final stretch for the day and the end is literally in sight - the scree filed at the bottom of Grays pas you can see from here is within about 300m from KBC
Grays pass itself for the next day: I reccommend starting as early as possible, as the sun will catch you somewhere around the middle section and there is no shade on the pass itself. It is also fairly steep. The initial section is “easy” and not too steep, the middle section is very steep in places but then it tapers off as you approach the cliffs. Awesome views from here. In no time you’ll be ascending the final gully and then about 70m or so from the top of the pass a nice picknick spot awaits you. Not sur eif you want to spend the rest of the day here (you should get to this point before noon if you started early), you can have alook at Vultures retreat on the right, or go over the ridge to your left as you came up the pass to go check out Moncs Cowl itself - highly reccommended.
Nkosazana cave is about another 400m or so to the left as you topped out, but on the right hand side of the valley (i.e. the Lesotho side), in the lower rock bands.
I assume Ships would be your day 3? If you are fit you can make it from here back to Moncs Cowl, but you would then be in for a long tough day of hiking. If you do the return leg over 2 days it is really not too tough. Ships Prow Pass is not technically difficult (Grays pass is probably more technical), but you start from a very high point (on of the highest passes in the berg, on average 300m higher than the rets), so you will feel it in your legs. Also, if you start from Nkosazana cave you are in for about a 3km hike rising about another 300m ASL, so your day 3 will work your legs a bit. The pass itself is mainly grass covered and no real path (although you will see some sort of faint path going down the pass). It’s long and the last time I did it there was no water to be found anywhere until way down below, so make sure you take enough water before you start this pass, as you will be walking in sunlight the whole way.
The biggest difficulty with Ships is not the pass though, but the horrible bushwacking section in the riverbed. It’s only about 2,5km’s long, but your progress here will be slower than the pass itself (we were even slower here than ascending Ships!). Factor this into your time planning. Stay to the left as you descend the riverbed section, there is a path here. You will lose it in places as you go over rocky sections, but just follow th egeneral direction down the riverbed and stay to the left, then you will find it again.
One of the best camping spots I’ve ever been to in the Berg is at the bottom of this river section. I’d make this my overnight spot for night 3 if I were you. It is just to the right of the middle of the river bed about 400m or so before you exit the riverbed. Here’s a couple of terrain markers to find it: On the left you will see a section of smooth rock from fairly high up, black in colour and if there is water forming a couple of waterfalls going down to the river. This is the only waterfall smooth rock section at this point. On your right you will see an arching erosion wall with a couple of broodbome at the top (if the ground gave way they will not be at the top of this erosion wall anymore)… Again, this is the only erosion wall at this point, and if you know what to look for you can even see it from the top of Ships Prow Pass. If you draw an imaginary line between these two markers you should find the camping spot. Watching the sunrise from here the next morning as it shines on the pass is super spectacular.
Day 4 is then an “easy” 12km’s or so back to camp. Easy after days 2 and 3, that is.
In summary, Ships isn’t a technically difficult pass, it’s just really long and you will feel it in your legs. And be prepared for the bushwacking section at the bottom, it IS worse than the pass. In fact, if it wasn’t for this section many more hikers would do Ships Prow pass. Still, that camping spot in the riverbed will make all the hard work seem worth the effort.
(PS: Have a look on www.vertical-endevour.com for tracks you can download of this route, as well as other Berg related info)