You can read the introduction to The Red Pony at books.google.com. You can also read a portion of the book at amazon.com. Search for the title, then click on the link to "search inside this book." This book is still under copyright, so it is not yet in the public domain for free access. You won't be able to read the entire book online unless you purchase and download it from a bookseller. For instance, amazon has a Kindle edition, and Barnes & Noble (bn.com) has a digital ebook.
I'm sorry that I can't be more helpful to you than this. Good luck!