My husband and I went on the KTTK tour one time, and we loved it.
We picked the first tour of the day. We were admitted into the park before it opened to register and wait for it to start. We were free to wander around the empty MK main street area. It was such fun to actually see what was in the store windows and to take our time and check things out. It was also a little strange to have the place be so empty.
The tour was wonderful and our guide was really into the history of the MK. It is a walking tour, so if you can't walk the 4 hours (I think that was what it was) with little break time, that would be something to consider. We ended with a tasty meal which was really good.
I would do it again, but in another park. There is so much to see and learn; things you walk by while in the park and don't pay attention to. It enhances the experience for you. There is no way it would interfere with your experience in the parks. Have a great time.