My big find this summer was this Perla bed. It's plastic, so while not mouse-chew-proof, is not mouse-desirable, so it can be left out for the winter no problem. It's raised slightly of the ground, with vents in the bottom. I saw these on the British edition of It's Me Or The Dog and thought they were brilliant.
The finishing touch is the West Paw Blanket. This is the same blanket I use for my acupressure clients, and it's versatile during road trips (covering the cooler in the car, tossed on the floor in the hotel).I invest in the big size that can be folded or spread out as needed. It washes up easy as pie.
While the previous photos show the outer edge of the porch, the final placement is between my bed and the building, so she's less exposed to weather and woods ("what was that!?"). So far so good!