if you're aready doing 75 mile rides you'll do just fine! What's the swelling in the knee due to? I strained my IT band and finally got that issue taken care of, but man, it was brutal for a while... Aleve was recommended to me by my doc as an over the counter anti-inflamatroy... before every long ride I take one now... and on a century ride I take one pre-ride and post-ride... seems to help a lot.
I'll jump back on before the event and maybe we can figure out a way to identify ourselves... it would be cool to say hi!
There is a fine line between "hobby" and "mental illness".