You can do better than your $25 Le Tour for this event. Set a reasonable budget and look around for a nice Miyata, Italvega, Univega, Nishiki or similar 80's bike that will be lighter and take appropriate gearing and tires. I think you can put together a completely acceptable ride for under $500 if you shop carefully (now is a good time to buy tires, tubes, etc.) that will give you pleasure far beyond the end of Eroica. In fact, I know a guy who is selling a very nice Mondia that was ridden twice in that event that is ready to go and could be had for pretty much that price plus shipping.