If you have strips or an actual jelly roll or two then try a "jelly roll 1600" or a "jelly roll race" you can piece a quilt top 50x 60 ish in less than two hours and I am NOT kidding. Add borders to make up the size or use more strips in the first place to make it wider. If you have to cut strips it will take longer of course. then just simple walking foot on wiggle down the middle of the strips and you'll be done in a flash.
I did make a simple chequerboard quilt for my husband in 12 hours flat when he went out for the day once, it was cross hatch quilted and that quilting is now breaking down. the wiggle method is more hardwearing than straight lines.
For the kids you can use less strips than the 40 width of fabric ones.
Best Becks