The nice thing about Hotel Coronado is that you can spend a lot of time there walking around, looking at the different things they have and eat there without ever staying overnight there. Be sure to check it out if you have time.
My sister-in-law is a keeper at Safari Park, and even still, I'd agree with this. But I also think it depends on how old your kids are. Mine is little and the zoo was a little better for her - she'll love Safari when she gets older.
Sunday or Monday should be fine for the zoo, so if you're doing something else that will be crowded (beach) I'd do that Monday and zoo Sunday. Definitely avoid the hill by the polar bears as PP said, especially if you have a stroller, it is killer. We used to do the hill circuit for exercise when my kids were babies!