I bought The Secret Garden in that series a few weeks ago. Still way too difficult for me, but I was very proud of myself for having deciphered the first page with the aid of Pleco. I can understand John’s logic for nof including the pinyin, but it would be really wonderful to have it, or at least an English translation.
If by any chance you are a family of polyglots, you can get more Verne in here in quite a few different languages. Librivox is a website I really love:
Here is what they have in Chinese. Most of it seem to be poems, and of course since they are read by volunteers, you never know about the quality of the accent: