I don't think I'd bring fleece for 70° weather.

How are you camping/sleeping? Bringing a sleeping bag? So will you be out and about in the middle of the night?

St. Louis has a wicked habit of having sunny weather in the morning, then clouding up with thunder showers in the afternoon. I'd be tempted to bring a lightweight rain slicker which would double as a long-sleeve shirt or warm top. No need for additional fleece.