Just got back from two nights in Mapungubwe park - what a lovely park it is. We experienced relaxed and very friendly staff, excellent accommodation, highly recommended.
The drive was 6 hours from JHB, last shops/petrol in Alldays. We had a 2-person chalet at Leokwe camp, beautifully designed and very good value at about R800 (we paid the same for a pretty bad, dusty campsite at Etosha a few weeks ago). All chalets are very private, and the sense of being isolated in the bush is fantastic.
The park is still fragmented and a bit strange to navigate; we were one of the few without 4WD and were somewhat limited but still got to see lots. There's an elephant fence (electric wires spanned above impala-height) with signs explaining they want to keep elephants away from the riverine forest to allow this to return to the state it was when humans kept elephants at bay) but this was broken in any places and elephants were all over the place, freely crossing in from Botswana and Zimbabwe, it seems. I think the park would benefit if they simply removed this and the other toppled-over fences we saw across the eastern section. The only minor annoyance was some rubbish in the park, apparently from the schoolbuses that regularly enter the park; some cans and bottles below the treetop walkway and along the main roads, pity.
Anyway: the treetop walk at 6am was magical as the forest woke up, with elephants and bushbuck browsing right underneath the platforms and 3 brands of kingfisher. Saw my first eland (never spotted one in 4 KNP trips) from the confluence viewpoints.
Later, Cedric gave us a very good tour of historical Mapungubwe hill (with lots of game and a huge mamba as a bonus).
We did a night drive with Leonard and were the only ones in the jeep; he was a great guide and though we didn't see big cats, we were very very lucky to see an aardvark on the road! Leonard hadn't seen one in 15 years of guiding at Punda Maria and Mapungubwe, so he was very happy too

The 2008-architecture-award-winning information centre building is unfortunately still not ready (in the various brochures maps you read "Opening in 2008/2009/2010") but repair work on the roof was ongoing and guides told us it will actually be open this October.
We finished off with a quick visit to the bird hide in the western part of the park where a large herd of elephant were busy munching through the pretty forest, and dozens of warthogs were having a bath. I'll need to return in summer for better birdlife.
A small but very enjoyable park, great for those who don't insist on seeing the big 5 and enjoy the peace and landscapes - I'd certainly return when the info centre opens and they manage to link up the sections better.