Tennessee update: While the emergency vet only found a slight fever & not much else (based on an exam, not lab work or X-rays) and gave him fluids & anti-nausea meds, he's still not eating & still hiding out.
Thankfully, his great local VCA vet is in today; I dropped him off so she can fit him in, between appointments. (There are no appointments left today.) Spoke to her as I was doing the drop-off, too.
He *did* have enough energy to resist getting into the cat carrier.