Oh, that's a super petty concern. People omit dangling participles all the time.
Funny story: I would have no clue whatsoever that it's considered a problem by anyone if it wasn't a thing that was brought up in in a King's Quest VI quest. The game explicitly tells you that "Where are you going?" is an incomplete sentence and needs a "to" tacked on to the end of it to be complete, but I don't care, I actually prefer the "incomplete" version.
But I think there's a difference in the sentences Julie. "Where are you going?" I agree is perfectly natural, but the answer does not require the preposition "to" so neither does the question, whereas you have to "tell something TO someone", you can't just "tell everything her".
It can change the meaning of the sentence, eg. "I have a few people to read" would mean I have collected some people I want to read a passage at assembly, whereas "I have a few people to read to" means I need to read to a few certain people.
Another native speaker (American) says,
"cindy has only a few friends to tell everything to" is perfect.
What i'm having trouble with is the "but they are her true friends?" part. It's probably trying to say "and they are her true friends" or "but are they her true friends?" because "but they are her true friends" doesn't make sense in this sentence.