You would really like the Northeast Missouri area then if you are looking for "small town americana"
There are towns ranging in size from 300 people to 17,000
Namely the towns i have lived in, which have the feeling you are looking for include where i grew up (monroe city, mo) which is 20 miles from Hannibal, MO with 2,300 people. Palmyra, MO which is approximately about 2,200 people, and is approximately 10 miles from Hannibal, MO and then of course you have Hannibal, MO which is around 17,000 people, and offers the small town feel in some of the neighborhoods, but at the same time has a JcPenny, Goody's, Big Lots, Walmart Super Center, Walgreens, Steve and Barry's, and of course many fast food restaurants in the newer part of town...
In this area of missouri you can easily access the following: Mark Twain history (both where he was born, and where he grew up), Mark Twain Lake (a Corps of Engineers lake created by the Cannon Dam) and is around 18,000 acres of water, and is Northern Missouri's largest lake (25 miles from Hannibal, and around 15 from Monroe City) The Mississippi River, which runs along side Hannibal, MO. Also Northeast Missouri was home to many Civil War battles if you enjoy history, there are also many 120 year old homes in this area... they sell very reasonably, or if you prefer you can buy a newer home..
Here are some local links for you:
http://www.marktwainlake.com/
http://www.hanmo.com/
http://www.visithannibal.com/
ALSO: Northeast Missouri is anywhere from 3 hours to 1 1/2 hours from St. Louis, MO (Hannibal, MO is 2 hours)
If you need any help figuring out Missouri, just contact me via a personal message here on the board
