There are tons of free and safe trips in St. Louis. Check out a few at (http://hubpages.com/hub/M...)
Cahokia Mounds, 30 Ramey Street, Collinsville, IL 62234 (http://www.cahokiamounds.com/) - located just across the river in Illinois, this is the site of the largest pre-Columbian city north of Mexico and has been designated an official UNESCO World Heritage site.
Alton, Illinois is a historic river town just across the Mississippi River from St. Louis. Enjoy wineries, winter eagle watching, 50 antique shops, 9 golf courses, historic sites, fine dining, and elegant bed and breakfast accommodations.
For a scenic day trip, take the Great River Road (http://www.greatriverroad.com/) north from Alton to Grafton (http://www.grafton.il.us/), stopping for antique shops and then on to lunch at the Pere Marquette Lodge (http://63.135.118.189/) in Pere Marquette State Park. This drive is especially beautiful in the fall months, but in the winter you can see a number of bald eagles roosting along the river bluffs.
St. Charles - nearby and makes a nice day trip.
Jefferson City Take a short trip to the state capital!
Troy - only a short ride away.
The Katy Trail State Bike Trail
(http://www.bikekatytrail.com). The Katy Trail is a bike path built where a Kansas-Missouri-Texas railroad line formerly ran. It's over 200 miles long, and biking on a section or the whole thing and stopping on the small towns dotting the tree-lined trail is a worthwhile excursion. Great place for bikers, runners, and those who want to experience small town Missouri and the great outdoors.Lewis and Clark State Memorial Park
(http://www.campdubois.com) Camp Dubois where the Missouri River joins the Mississippi River. On the Illinois side, about 15 miles from the Gateway Arch. Take I-70 North to Exit #248A McKinley Bridge, then Hwy 3 north towards Alton, exit at New Poag Rd. Hwy 203 and turn left. This is the location that explorers Lewis and Clark stayed at to begin their journey to the Pacific in 1803-04. Short hiking trails, 82 campsites, 1930s lodge, popular for family picnics.