Ok. This is what i come up with:
1)Our mesozoic survivors most be only and strictly from South America
2)The book will be divided in seven sectioms,each one from every cenozoic period:paleocene,eocene,oligocene,miocene,pliocene,pleistocene and holocene
3)The first four of this chapter will be concentrated only on south america,since our non-avian dinosaurs and eventually other cretacean reptiles descendants won't go outside the continent and will stay almost exclusively in there. Is in the fifth one that we will concentrate also on North America,with the isthmus of Panama formation. The others two chapters will be concentrated also in Africa and Europe,with the ice age. It will be you to decide if it should be better divide or not this sections in various chapters.
4)For all the book's sections a narrator will describe,in a scientific but enough understandable and charismatic way the environment,the animals and also what will come after the period he describe(he have to attire the reader's interest,you know). Almost exactly like in the "Walking With" series. Also,if you want...we can also add some illustrations,to better describe this things and some "behind the scenes" chapters.
5)We won't describe only non-avian dinosaurs:we almost exclusively will,in the first four chapters because of the fact that,since they will be limited only to the south america they on't affect too much the rest of the world,that,so will be almost identical to our's. But we will describe at least partially other animals class,that existed also in our world,like sabertooth tigers or ancient proboscideans because they will interact with our alternative dinosaurs and probably will take different ways:it can be entirely possible that animals like mammoth will not exist or exist aniway,but in a very different way. We will have to describe,in short the different consequences that some survived south american non-avian dinosaurs will create,in the rest of the world.
And...that's all,for the moment. I hope that could be enough,for you,to define at least partially the new book's scheme