The hottest period in South Africa is during the months of November all the way to March. This period is also the busiest in terms of tourists. If you'd rather opt for cooler temperature and less tourists around you, then the months of July and August are also great times to spend in the region.
As a general rule, the public transport in South Africa is definitely not the best in the world, but the roads are quite good. Therefore, it would be best and easiest to simply hire a car, or take advantage of the Baz Bus, which is an extremely affordable bus (hop-on-hop-off) service for backpackers. you may also want to look into booking an organised tour, which would turn out quite affordable as well.
The currency of South Africa is the Rand (R). The Rand is not as strong as the Euro, Dollar or Pound, which means that you'll ultimately receive more for your cash. Eating outside, getting a place to sleep and the top attractions will all be extremely affordable for the average tourist. Credit cards may also be used in the vast majority of areas.
Everybody is on the same boat
If you are travelling to South Africa all alone, then don't worry, you're not the only one. The vast majority of travellers are alone as well and most striking of conversations on a bus or hostel will most certainly be well received. You'll probably see the same people throughout the entire journey as most travellers going through a similar route, so you'll make friends quite easily.
Even when having plenty of fun, you'd still need to make sure that you are on safe grounds, as some areas in South Africa may be a bit dangerous. However, if you keep this in mind during your trip, and remain with a group of individuals, with the tour guide, at the hostel/hotel or the tourist bus, then you shouldn't have any problems at all. Obviously, it is advised not to walk around all alone after dark, and make sure to be with a group of people when taking money out of a cash machine. Always make sure to have your accommodation name when you're away.