I don't think you're crazy for touring on a mountain bike -- infact, I doubt I'd even consider touring on anything else. If you're anything like me you'll still be tinkering with your route right up until the very last (even after you set off), and only a MTB gives you the freedom to go literally wherever you like on a whim (or on local advice which is something I've come to rely on for touring).
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I am clinically insane. I am proud of it.
That is all.