Hey Chicagogal!
When I first joined TE last week, I wanted your screen-name, so it's only fitting that I actually get to write to you now!
Which Century are you riding? That's my training goal, too: The longer the ride, the happier I am!
If you ever want a riding partner, I would love to meet up. I have done the North Branch, too, and I have met some very nice people on the route, but it would be a pleasure to actually intentionally do the ride with someone. Now that I have a new Cannondale Synapse, I am sure I could keep up with you, too!
BTW, if you do look for a computer, get a Strada Wireless. It's so small and easy to install, and super convenient. I had one on my Road Warrior until Kozy's lost it for me. That's a whole other story, but I am still waiting for my replacement so I can guage my speed on the new Synapse. Nothing like crappy service at the closest LBS to my house. 
Congrats on the great experience today!
There's only one thing better than spending a day on my bike: Spending a day on my bike in good company.