Meramec State Park is a possibility. The park wouldn't have had many visitors on a weekday that early in the year. If she wandered off, a closer possibility would be the big stretch of woods between the south side of the city and Pump Hollow Rd. All Betty would have needed to do is go out past the fire station to South Church St., turn left and follow it to the end behind the elementary school. The woods begin right there and are very dense with a long stretch downhill. In mid-April, she may have wanted to go mushroom hunting, there are a lot of morel mushrooms in that area. She may have wandered quite a distance back there.
Yea that's why I'm interested. Although I haven't seen much predator activity like vultures, coyotes etc. But who knows! Probably gonna check the tracks headed toward st Clair.