Real Simple's packing guide has been helping me take the stress out of packing for family of 4.     Roll It, Fold It, or Bundle It Rolling and folding are classic expert-packer methods; bundling is advanced—but ingenious. Rolling Great for: Unstructured bags, like a duffel or a carry-on tote. Stretchy knit fabrics that are unlikely to wrinkle, including T-shirts, workout pants, light