Bob, nice troubleshooting link.
Mud daubers can be controlled by aftermarket screens. This Camco item for Atwoods isn't exactly like the one I have but look around. However it won't necessarily keep spiders out.
Ithaca, NY, wouldn't duplicate altitude problems I had in August. My furnace wouldn't light at 7000' in Oregon -- probably needed the air-fuel mix adjusted. Returned to lower elevation and all has been fine.
Under the Atwood cover is this sticker:
Anybody know exactly where that flashing indicator is located? Is it something on the circuit board? Sorry that I didn't look at it when mine wouldn't light.
Wish lewster was looking in here...