Pumpkin in a lace stocking. I've planted a bunch of mini white pumpkins. White lace stockings on them might be a nice outdoorsy Autumn touch. Inexpensive and kinda unexpected. These might be cute on the outside tables under the arbor too.
DIY pumpkin decor for outside your home: Paint pumpkins if desired, add Uppercase Living vinyl lettering (can be custom created to use your last name, established date, etc) and tie stem with decorative ribbon. Artificial pumpkins maybe?
Metallic Leaf Pumpkins: Collect fallen leaves and spray paint them gold; let dry. Paint one pumpkin white and the other gold. When dry, use crafts glue to attach the metallic leaves to the white pumpkin, then arrange the pair together on your porch.