My Husband and I ordered this so that when we moved to an Apartment we would have a comfy guest bed as well as a comfortable enough couch. It will be perfect for the small space we anticipate. It is wider than I imagined it to be but only by a couple inches. You could maybe do an extra long twin, but it would be quite snug. Theres about a half inch of space on all sides of my regular twin mattress perfect for putting on sheets and blankets and the pillows cover all cracks. Trundle I would not reccomend anything more than 8 inches otherwise you wont be able to close it.