I also went to Disney Land (Cal.) last year with a 28-200 f/3.5-5.6G lens and my 50 f1.4G on my D800E. I used the zoom most of the trip as even on the rides, I figured most of these if not all maybe printed no bigger then a 4x6inch print. So higher iso's didn't bother me to use. I took a little over 1000 images in two days and I think the longest focal length was around 135mm, which would be ~90mm. So I would recommend the 16-85 as the wider end would be nicer to have versus the longer end. And for lower light, I would carry the 35mm f/1.8G.
If you are going to animal kingdom, then I would recommend the 18-200/300G and the 35mm f/1.8. I would keep it to a zoom to cover most anything and one small fast prime for night time picks.