Hey Mark!!
Please come join us
here in the Varsity Student Forumites room

Young adults sharing a love for nature in common and having a lekker time
1.
The cheapest accom is camping, but it involves needing space to pack camping stuff into

A bit of a challenge when you a bunch in one car, but can be solved if you pack a trailer

Half the cost of your other options
I would say the safari tents at CB and Skuks would be really awesome though!
2.
Petrol will probably be a tank there, a tank back, and some tanks in the Park. I use about R2500 on petrol for 6 nights in Kruger in my corsa lite. So I would estimate over R300.
3.
A lot

Best is to bring your own food of coarse

But there are fairly priced meals at the wooden banana at skuks, afsaal, tsokwane. I would not eat at LS restaurant if I were you

But I'm sure you could buy stock in the park and cook up a brunch at a picnic site, a braai at night, and snacks in between to keep you going

biscuits, rusks, chips, biltong, fruit and that sort of thing is a common Kruger diet
4.
the communal kitchens and bathrooms are usually in very good order

Bring your sunlight along, and remember to bring a plug for the basin! If I were you, I would just bring along enough clothing for the week, and not worry about washing until you back at home
5. Sightings boards are still around, although the pins are limited. If you would be willing to provide some magnets for the South, you would be a legend

Although these days people keep updated on the latest kruger sightings on latestsightings.com, or get the updates on twitter, BBM, or whatsapp. I am a compulsive updates checker, wanting to know what is seen where and when! So I will easily hook you up with getting the latest updates