What is the main climb like, as far as the grade? Someone says like 2-3 miles at 10%? I don't think I'm going to make it this year - unless it's some last minute thing, but I'd like to know in case I go next year.
While I've not done eroica, I've done a fair amount of epic rides like this on BITD. On pavement is a whole other thing that dirt. Main issue is that it's hard to keep the rear wheel from slipping. Getting out of the saddle will usually result in instant slippage. Count on climbing in the saddle most of the time. I always figure I need at least a gear or two lower to keep traction, especially if it's muddy. With really good technique, it's possible to push a bigger gear and maintain traction, but my technique isn't that good. I can't see crank length making a difference one way or another.