Update:
Replaced the PCV and air filter. Also put in some STP Oil Additive when I added oil (I added straight 40 weight). I just used the additive not expecting much, but it was cheap, so I figured what the heck - man that stuff was like honey!
Also got a full tank of gas ($42!) and put in some STP fuel system cleaner additive.
Looked underneath a little better and it still looked completely dry. It looked like it could have been slightly wet around either the drain plug or the pan gasket, but I felt it with my finger, and it was dry. I also did the cardboard thing and revved it up for a little longer this time - still no oil on the cardboard.
Looked closely around the engine both running and off, and could not find any evidence of a leak of any sort.
So after I got the gas and fuel additive in there, I reset the avg mileage thing on the info center. Now it shows only about 14 mpg, where it used to show about 19 - is this just because it will take more time to properly adjust (I hope so!)? I've only driven it about 15 miles or less since...
One other thing: While I had the cover off the engine after I replaced the PCV, I cranked it and it sounded like there was a vacuum line off or something, kind of a constant hissing - I looked at all the vacuum lines I could see and they all looked good - although I did see what looked like a nipple for a vacuum line connection that had no line connected to it, only a piece of foam covering it up with a clip sort-of thing around the nipple. It did not have any suction that I could feel with my finger, and the sound didn't change when I covered/uncovered it, so I don't think that's the source of the noise. Is this noise just normal?