I did this trip in October 2016 and it was fabulous! South Africa is such a beautiful country with so much to see. Cape town was brilliant and my highlight there was seeing the penguins on Boulders beach and going up Table Mountain on a clear day. If you plan to go to Robben Island you will need to book ahead before you go (unless JY have started offering as an excursion). When we were there I tried to book and it was all sold out... oh well, an excuse to go back! There were some fairly long coach journeys on the trip but totally worth it. Featherbed nature reserve from Knysna was stunning. Safari at Kruger National Park was truly a bucket list experience - you get so close to the animals it's incredible. I also did the Vic falls add on and loved it. Don't miss the excursion to Chobe in Botswana. JY offered a trip over the falls on either a helicopter or a microlight - i'd been on helicopters before so chose the microlight (even though i didn't know what one was!). It turned out to be one of my favourite experiences on any trip - there's a photo of it in my profile pic.

With regards to cash, I used USD for Zambia. I think you may need to pay for a visa on arrival at the airport so you'll need cash for that, I think it was $50 when I went. Some of our group took anti-malarials and some didn't. I took the generic version of Malarone which I bought it over the counter at my local ASDA pharmacy (much cheaper than going via the doctor) Take a fleece as it can be chilly on early morning game drives and take lots of memory cards. 

That's all I can think of for now, give me a shout if you have any questions  🙂