being 'in a book somewhere' doesn't automatically make something that's wrong, right... and i didn't say you can't have a ? in the middle of narrative... i said you can't have it in the middle of a narrative sentence... neither ? or ! can be properly used in the middle of a sentence, unless they're part of something in " "... and since there were no " " in the sentence i was referring to, it was wrong... you wouldn't write: would you? [if you would, it would be wrong]... so plunking a ? in the middle of a narrative sentence is just as incorrect and nonsensical...
Actually, yes, if rearranging the surrounding text to prevent this problem turned out to be a hassle, I would do that. I'm not going to put a thought in quotes, since it's not spoken aloud, nor am I going to say "He thought" before the thought, because I find it to be horribly distracting and awkward (maybe you don't; a difference in opinion). I don't care if it's nonsensical to anyone else; short of a better option, that's what I'll do. Coincidentally, just today, I saw a couple of cases where there's a question mark in a character's thoughts before the end of the narrative sentence. Admittedly, the author (Eoin Colfer) did not gain his fame for his grammatical know-how, but six books in, he's yet to be corrected. Clearly it's not as big of a deal as we're making it out to be.
I only use italics for thoughts when it's meant to be an "inner voice". You know, the one arguing with the character and talking to them in second person. Simple thoughts are ' ' by me.
If you are going to use italics for thoughts, I recommend reading Dune to see how it can be done well.
single marks [ ' ' ] can only be used for a quote within a quote... using them for anything else would be totally incorrect...
Unless you're in the UK. In that case enclosing external dialogue in single quotes is a standard which is graudually giving way to the US standard of using double quotes. However, it is still incorrect for internal (unspoken) dialogue.