Hi Peter,
I did this tour in Sept 2011 and had the most amazing time - it is still my all time favourite holiday! The Zambia add-on is the icing on the cake, it was fabulous. If you are staying in the Zambezi Sun hotel, there is air con - keep it on while you are out (I stuffed a piece of card into the slot!) and this will help to keep the mossies at bay but make sure you apply DEET morning and evening. Take the Malarone after a meal that has some fat content in it, as this aids absorption. I used to take it after breakfast as it was hard to remember to do so after dinner!
Speaking of baboons, we were advised to make sure to keep our door closed in case any wildlife got in - there are zebras, monkeys and other animals in the hotel grounds. In a humorous manner, we were told that if monkeys got into our rooms, they would make a right mess - BUT if baboons got in they would have a party and wreck the place! They have been known to open wash bags and squeeze the toothpaste out etc and generally go mad! You have been warned!!
Have a fantastic time - and make sure you do all the optionals, they are worth it!
Cheers,
Bob