the funny thing is, I had the thought that that pony that is apparently faceless named ditzy doo was probably the author, and she used a pen name, as many do, to disguise herself. I then thought that she probably idolizes RD for being cool, and wishes she was like her, so she made a self insert character to live through vicariously because she screws up all of the time. I only bring this up because Ditzy doo was Derpy's beta name until they chose to throw their fans a bone, but you already knew that last part of course.
Hm, that raises an interesting (to geeks) question: are the Daring Do novels only "original" pulps written several generations ago and forming a closed set, or a currently active series so that Dash could reasonably expect new books to come out? Of course, it could also be a mix, a series like Tom Swift that gets revived every generation with new stories. While there's heavy direct homage to the Indiana Jones movies, that doesn't automatically mean that Daring Do is a modern character based on an older style.
And another thought occurs to me...does Equestria have movies? We'd know by now if they had television, but like the bowling alley the local movie theater (which probably shows a lot of oaters) might simply not be important enough to the main cast to show up regularly. Especially if the general social level is analogous to the late 1800s (leaving aside anomalies like the bowling alley) as seems to generally be the case...movie theaters may only be in places like Manehattan.