Signed all the papers! It didn't even take that long. The only minor wrinkle was that I'd already wired the closing costs using the amount they told me on Monday, and that was about $169 less than the total on the paperwork today. The problem was they'd included the cost of the mobile notary into the closing costs, when on Monday they planned to have me write a separate check. I didn't want to have to do a second wire for $169 since there's a $20 fee for each wire transaction from my bank; fortunately they agreed to let me write a check for the $175 mobile notary fee and said they'd fix the papers.
So, future reference: don't wire the funds until you see the paperwork and the total amount on it! That was probably a rookie mistake; ah well. I've also pored over the GFE vs the actual closing costs, and can see they estimated very high on a few matters, explaining the costs being even less than I expected.
It's a bit anticlimactic without keys in hand. At least I accidentally kept the notary's (cheap) pen.