Defiance is a good suggestion for starting point, because it's not far from your location (Foristell), and if any of your girls do not have bikes you can rent from the bike shop there. The one drawback to Defiance is that parking can be limited on weekends. The two bar/restaurants there cater to the Harley crowd, but I've never felt uncomfortable in either place. In fact I've gone to both the outdoor "patio" section of Terry & Kathy's, and the indoor restaurant part of Dave & Jacquie's, with my two small kids. It just depends on what you're comfortable with.
This is a great section of trail, but if your girls are looking for scenery and river views you might want to consider heading out west to
Rocheport. It's a much farther drive (about 90 miles from Foristell as opposed to maybe 15 miles to Defiance), but higher on the "cool" scale. Rocheport has a
railroad tunnel you can ride through on the west end of town, and the trail hugs the river heading east from there for some fantastic scenery. You'd probably go to
Huntsdale, grab lunch at Katfish Katy's, and head back for a 13 mile round trip. Or
McBaine for a 17 mile round trip. There's a really amazing
burr oak tree just off the trail near McBaine. Katfish Katy's isn't really a restaurant - more like groceries & supplies. Also, there's a bar & grill in McBaine -
Lucy's