user149 I read the Island of Adventure to my DC, I had to talk to them about:
why you shouldn't keep a meeting with a new adult a secret from your parents
Why it's wrong to go without your parents knowledge and spend time with strange man
Why it's wrong to get in strange man's car
Why it's wrong to secretly go to dinner in a hotel with strange man
Why it's wrong to take sailing lessons with strange man
Why it's wrong to steal the family manservant's boat
Why it's wrong to be so rude to family man servant.
Why you should not sail stolen boat through dangerous waters to an island after being explicitly told it's dangerous.
Why you should not climb down a rusty old ladder into an old mine works on island.
And that's without addressing the general idiocy of the main characters, the main characters continual lying, general sexism related to the aunt and female characters and reading an updated edition that removes all reference to the manservant's race.
I'm not advocating throwing them all out and never reading them again, I was just cautioning the OP that they can be problematic. Just how problematic they are may depend on which series.