I'll be riding with a seasoned century-rider, who is also a very good friend. I'm not intimidated by it, since I'm quite comfortable on my bike and I've done long rides before, including tours of several weeks.

Thanks for all the advice. I do need to get on my bike more than I have been. One drawback of working from home is that I no longer have my hour commute twice a day (of course, I COULD just go out for a bike ride, but something about a commute made it easier to get out).