Just more for reference reall for future readers.
I have just returned from my second visit this year to Kruger. Alone, 5ft nothing, and female, with a camera bag (Lowepro mini trecker AW) and handbag. Between the handbag and camera bag, they contained Canon 7D and 80D bodies, (brilliant in low light by the way) 1 x heavy 2.8 70-200mm lens, 1 x heavy 100-400 Mk II mm lens, and 2 small lenses, plus full size Zeiss binoculars that are also heavy and a handbag with ipad mini and pocket camera. (I actually put the binoculars and one camera body in my 'handbag' and 'distributed the weight').
My experience with this flight, and a similar one flying to Swaziland, is that the cabin baggage destined for the hold, tends to be the small suitcase type with wheels), or the very large back packs.
Both my camera bag and handbag came inside the cabin with me on Airlink from JNB to Skukuza and easily fit into the overhead storage with handbag underneath the seat. The flight was full with the exception of one empty seat. It's a cracking flight, beautiful flying over the bush too. The flight is 45 mins, and check in etc, is really no problem as it's a small regional flight, on an Embraer 135 (or is it 145?). Anyway, lots of people carried they hand luggage to the steps of the aircraft, and they just loaded it in the hold. I would have had no problem doing this with my camera equipment. There are a lot of people with some serious photographic equipment going to KNP, and I know from reading TA, that some of them are checked into the hold with no apparent problems. Interestingly, on my next trip, I think I'll leave the 70-200 at home, most of the photos were taken with the 100-400mm lens! But I digress....