I think maybe there's some ambiguity of word choice here that might be confusing the issue. I interpret "barely surviving a gang of rapists" to mean "being pursued by aspiring rapists and barely getting away unraped," but it occurs to me that it could be read as "being violently gang-raped and barely living through the experience." So perhaps JRoss is interpreting the phrase the latter way, which makes it sound far worse than the former would. Therin, would you clarify which of those you actually meant when talking about Gaila in the Academy novels?
(Where Tasha was concerned, it was never made quite clear in the show, but I think the idea there was that she didn't escape unraped, and I think the novel Survivors suggested that pretty strongly.)
IIRC (I can't pull my copy of The Assassination Game right now, but I think I would remember an explicit rape), Gaila is definitely not raped; I think that it's the sort of thing where the gangs are mentioned as a problem and Kirk tells her to be more careful about where she goes in the future. It was at the beginning of the book, and the idea of rape gangs on Earth in the TOS era was...more than a bit disconcerting and unappealing, really, but there wasn't anything graphic.
But I'm re-reading
Survivors right now, and I can say definitively that it confirmed Tasha was raped (and is probably the most explicit that any of the books in description save maybe New Frontier and Soleta's mother); the book talks about how the rape gangs caught Tasha, "forced her to submit," and "took their turns at her." The whole description constitutes maybe a long paragraph or two.
With regards to censoring Star Trek books for your kids based on content, though, I really think that it should be more of a "read the same book and discuss as needed" situation. I mean, I started reading the Star Trek TNG numbered novels when I was about 7-8, read them all, and was fine - if my mom thought there was anything that needed to be discussed, we discussed it, but if I
could read something then my parents generally weren't going to discourage me from doing so.
If something was really concerning, then my parents would put it on hold (I wasn't allowed to read Anne Rice's Mayfair Witches books until I was in middle school, because of the very explicit rape and incest, and I'm pretty sure they probably kept anything pornographic like the sci-fi story you mentioned out of my view), but I can't remember ever being told "You can't read this book"
ever, or without being provided a reason. Again, I think the best approach to take is to read something and then discuss it - which I think is what it sounds like you're doing, JRoss.
As a matter of literary quality, I'd generally avoid the new Trek YA novels, like The Edge or The Assassination Game, but that's just because they're not very good. If you want to introduce your daughter to Trek and feel strongly about not wanting any mentions of rape or murder, then the old YA books are probably best - Worf's First Adventure, Capture the Flag, Prisoners of Peace, things like that. But I think the numbered Trek novels are fine for kids, even if they do have a description of rape (Survivors), murder (...a
lot of the numbered novels), or just disturbingly-described death (
Chains of Command opens with an away team accident in which a redshirt crewman's skin bubbles and dissolves.)