Thanks for the link to the auction -- looks like a great deal.
I think 2 nights would enable you to enjoy what Rovos Rail has to offer (though longer is always better!). I'd rather start in Pretoria and end in Cape Town, perhaps with a stay at the Nellie (Mt Nelson Hotel) or the Twelve Apostles (both LL proprties).
They do a Cape Town to Vic Falls journey which I have my eye on:
We've never been on anything this exotic but it sounds wonderful - I'm daydreaming already. One classsic train trip is the Algoma Railway out of Sault St Marie Canada. This is a beautiful wilderness train experience. You can pleasure ride for the day - or you can take camping gear - even a canoe for an extra charge - get off at any point and arrange a pick up time at the same point. This way you could wilderness camp for as many days as you wish. Sounds great!!! The pleasure trip was exciting too - over tressel bridges etc fine opportunities for photography Happy Travels...Funtimes