Don't do any research on how quilts like this have been done before. (Remember, you want this to be terrible.)
Choose your fabrics randomly, based on what you like and what you have on hand. Feed sacks are often loosely woven and can be stretchy, so they are great for this.
A walking foot or the equivalent is absolutely necessary for this kind of quilting. Make sure you DON'T use one, just use your regular sewing machine foot.
Eventually, probably before the quilt is finished, your sanity will return, and you will realize how really terrible the quilt is. At this point, you can store it in the closet (way way back in the closet). If any of your quilting friends find it, you can make up a story about rescuing it from a dumpster and keeping it around for laughs. Or you can just sigh, pull up your big girl pants, and finish it.
Adding fancy borders and special quilting to it would be like putting lipstick on a pig. The pig might be flattered at the attention, but in the end he's still a pig. A simple finish will get this thing out of the closet.
The baby can play on it, and you won't even care if he spits up. You can take the quilt on picnics in the park or to the beach. The grand kids can run their cars on it. You can throw it in the washer and dry it on the clothesline and not worry about using it up.
It is, after all, just a terrible quilt.
I'm wishing you good quilts and happy finishes this week.