Thanks for the input! The ultra cycling website has some very useful information which I haven't seen before.
Muirenn - I guess maybe to explain my beginner status a little more: I've done two summers of some road biking, just not long distances (typically my rides were between 15 and 20 miles). I finally upgraded my bike the end of last summer, so I think a bike with a proper fit will make a big difference. (I upgraded from an 80's trek with down tube shifters to a bottom line Madone)
I've also done some spinning, etc at the gym. I think within the first week of riding, I'll easily be doing 20 miles, including hills, etc.
So by beginner, I'm not just figuring out how to bike, clip in, etc, I have been doing that for a while, I just haven't done the distance yet.
Does this give you a little more hope for me? Just want some input on whether this goal of mine is really that out of reach, or something that is possible as long as I'm willing to put in the time...
Thanks!