To be honest, this isn't about gear choice... it's about philosophy. You and your wife need to sit down and discuss 1) what you want to achieve with the pictures from this trip; 2), what quality if images will be 'good enough' for the intended use; and 3) what her tolerance will be for you lugging the gear, changing lenses, and having the camera in front of your face for much of the time.
Once you've made those decisions, then picking gear becomes straightforward, the gear determines the bag, etc.
This is good advice.
Depending on how much time and attention you give your gear, you may miss certain experiences altogether.
I too was excited to capture as many shots as I could when we visited Disney last spring; however only 250 photos made it to our coffee table book, from approx. 750 keepers from well over 1250 frames.
I had one lens on my SLR and a Powershot.
I spent less time messing with my camera and a lot more time with the kids.
Was this a trip to Disneyland? Did you go to the zoo or seaworld? Also what lens and powershot worked for you. For me my current kit works fine but there are many times even at home I want more reach so I figured the 70-200 F4 IS will do just that but having a hard time justifying the money now which is why I am asking also I want would have to lug all that on and off of a plane. I would of course only bring the 70 to the needed attractions.