I've made a table runner with jelly roll but it was starched and pressed so maybe it got
a little preshrunk there. I also used Pellon fusible fleece. I washed it on gentle cycle with
cold water and dried it flat on a towel. If you wash the top you might get a lot of fraying.
You could try soaking it in hot water then drying it flat on a towel. I find table runners and
wall hangings to be more delicate to handle than quilts. You might want to offer the recipient the care instructions as well.
If you soak or wash, don't forget to so the same for the backing and binding.