Built by Boone and his son Nathan, this two-story stone house is open for tours. While you're there, you may want to take in the entire Boone Village, a reproduction town complete with reenactments of life in the period. To get there, take Highway 94 south to Highway F and go east. Tours are $7 per adult; $6 per senior.
Excellent biking trail. Rent bikes on Main Street and pedal as far down the road as you like. Or do as I do; just stroll through Frontier Park and take in the luscious scenery along the river. It's especially wonderful early in the morning, just pre-sunrise. Then head back to Main for breakfast or brunch at a sidewalk cafe.
Main Street has a couple of wineries, but if you want some with vineyards and sweeping vistas, head south on Highway 94 to Augusta (about 36 miles from St. Charles). Hermann, Missouri also has excellent wineries. To get there, take Highway 70 west to the New Florence exit and head south for some of the best wines anywhere.
World-class casino on stationary riverboat. Slots, cards, roulette, etc. Also offers big-name performers & entertainment. Seven or so restaurants, nightclubs, bars on site. Amerisports has mega-TV screens; great if you want to slip away and watch Sunday football. Within walking distance of the Main Street historic district.