I use a vinyl table cloth to lay on the ground with the flannel side up and then lay a blanket over it. Years ago I also had the vinyl pad from a play pen that had given up the ghost and used that until it too wore out. That was really good because it was lightly padded and stayed in place better than the table cloth. You could put some grommets in the corners of a table cloth and stake it down to keep it in place and then lay the quilt over that.