Over the weekend we also went to Chester Zoo. We had a fabulous day.
There is a lot of walking to be done and our feet hurt by the end of the day! There are suggested walks of varying lengths marked on the free map they give you. There are signposts all over the place to help you find the animals you are after.
It was very easy to find via road and we had no problems getting there. Overall a thoroughly enjoyable day out. Great value and fun.
We didn't actually manage to get around all the animals so I can say with certainty that you can easily fill in a whole day there!