Good recommendations from savage24. Here's a full list of
all campgrounds along the way.
The vast majority of the "locals" along the trail are
more friendly than what you usually encounter in urban areas. As long as you stay off of the private property along the way, you'll most likely experience nothing but friendliness and overwhelming hospitality.
Personal safety: you're far safer on the trail than on the streets of your hometown St Louis, where there always seems to be some guy in an SUV trying to assert his dominance over us lowly bike riders (OK, maybe it's not
that bad, but I ride often in suburban St Louis, and there's a reason why I prefer the trail).