Well, there is a couple things that we need to know... first, do you have kids under 16? They can't do Keys to the Kingdom. They can do the Safari though.
KTTK tour lasts about 5 hours or so, and includes lunch. There is alot of walking but you learn a TON of neat info about Disney and the MK. It is really neat going backstage and getting onto some of the rides (HM, POC, JC) through the back entrance and having a special ride.
I haven't been on the Safari yet, but I hear it is really neat and the breakfast afterwards is incredible! You get to be up really early and already in AK when it opens to the public. Much less walking and much more food!
Good luck on your decision... as far as the Safari goes, I know Samantha Brown covers it on the AKL special on the Travel Channel on Thursday, November 13th at 12 noon (can you tape it?). She actually goes ON the sunrise safari.
Have fun!
Karen