First, great job on riding anyway; I'm glad that you got beyond the alone-ness aspect and it sounds like you had fun! If it was a supported/organized ride, were there support vehicles out there somewhere too? If not, the total of 25 miles shouldn't have left you exposed or alone for too long, right?

I didn't drive 7 hours to ride in an organized event, but I did learn quickly (when I first started riding) that if I showed up @ 9/10 AM on either a Sat or Sun at a local park, that it was a popular starting point for weekend rides and many organized ones. If I wasn't meeting another newbie rider/friend to ride, I'd get to the parking lot ahead of time, get ready to ride and then wander over to gathering groups to ask about their plans (route, ride level, mileage, etc). Plenty of times, I got the cue sheet and map and followed everyone out at the beginning, telling them that I was fine on my own if I was dropped, but I also worked to hang onto the back as I gradually got experience and became a stronger rider. I only did this in the general Seattle metro area, but I also drove to many, many other organized rides with friends and, that was how I learned so many beautiful ride routes, that I've repeated many times over the years...fun!