Hello jetlag26, welcome to the forum!
You aren't kidding that options abound! This is a great place to get answers and do research. I used the forum almost exclusively when planning our first trip, and bounced ideas and suggestions off of other forumites when we went in May/June of last year. Our first trip we spent 3 nights in a private reserve and 4 in the park, and on our second trip we enjoyed 4 nights in a private reserve and nearly 3 weeks in KNP. Heaven.
To me, there is one camp that cannot be missed - Satara. It is a bit older and shows signs of wear, but the sightings are fantastic! It's smack dab in the middle of big cat country. I couldn't imagine going back to KNP and not including Satara.
My suggestion is that you don't try to cram too many camps into your trip, esp if you're looking at a week in the park. Spend 2-3 nights per camp so that you can enjoy the uniqueness of each and explore the surrounding area. That way you aren't taking too much time packing, unpacking, etc.
I'm not sure what flights you'll be taking from the Islands, but where to stay will depend on if you arrive in SA in the am or the pm. If you will be in Joberg in the morning, I'd suggest flying to Nelspruit and staying in a southern camp for your first night. (Crocodile Bridge, Berg en Dal, maybe Skukuiza, Lower Sabie or Biyamiti) Make your way north (including Satara
) and spend your last night or two in Tamboti. You can leave Orpen gate easily enough and make it down to Nelspruit to fly out. Morning walks are a must, and something I haven't done yet as my son was too young to go on them. But I haven't heard anyone on here say they are a bad idea.
Think about booking a bush braii, and do a few of the drives from camp. But don't over-rely on having others show you the wonders of the park - self drive is a fantastic experience!
Please ask away, as this forum is filled with helpful people.