Regarding the knees - are you by any chance taking glucosamine and chondroitin supplements? It's not a panacea, but it has helped me no end with the bits that go creak and crackle. For the rest: solidarity. It sucks.

I'm not going to be at WFC, alas. I can't afford it... and also, from Twitter, it's beginning to look like a trainwreck... But my plans for 2014 do encompass Worldcon!