Great trip report -- looking forward to more!
By the way, I don't think you can blame yourself for driving away from the shop without checking to see if they overfilled the transmission -- I certainly would have relied on their common sense not to do that. Just as when I get an oil change, I don't check the oil to make sure they put in enough oil. I wonder how many people actually do that?
On the other hand, I do double check the torque on the lug nuts after the tires have been rotated -- I don't trust the torque settings on those impact wrenches. Several times, I have found improper torque.