So won't you feel silly when you get there and everyone has a big white L and you don't? I'm a member of San Diego Zoo and also the Safari Park. L's and big Nikon lenses are very common, as are tripods and Monopods
I normally use my 70-300 however I have been known to take my 150-500 if there was something special I wanted. Inside (aquarium, reptiles, etc.) I use my 17-70 with an off-camera flash using a control cord.