All aboard for Dreamland! Hold on to your pillow because the Goodnight Train is taking off. Roll that corner, rock that curve, and soar past mermaids, leaping sheep, and even ice-cream clouds. You won't want to miss a thing, so whatever you do, don't . . . close . . . your . . . eyes!             With soothing, lyrical words and magical illustrations, June Sobel and Laura Huliska-Beith have created a nighttime fantasy that's guaranteed to make even the most resistant sleeper snuggle up tight.