I was one of the reveiwers on the first edition, so I read every word of it.
I think it would be good for a first time visitor to the parks, but if you have been a lot of times, you probably know a lot of what is in it.
I'd suggest going to the library or a book store to look at it. Because it covers many different special needs, a lot of people use a highlighter to mark the things they feel would be useful to them.