I think the moderating was just right. You might have reasonably stepped in sooner, but you erred on the side of letting things be while putting at ended to what needed to be stopped.
I'm a fan of not ruining a good thing by trying to make it perfect.
Cross-posting: we need more of it. Unimportant stuff, yes, we can encourage people to not dump everything into the main thread. But once I got behind the snowball I put my time into the main thread and had to leave some of the other threads alone for a while. When I finally got a chance to read them I was surprised to see some pretty significant content that never made it in to the main thread. I'm less worried about 10 more pounds of pressure in the firehose than missing important things. I say people should be encouraged to cross-post anything that people in the main thread would want to read/see.
If planting a Team F5 person in the bivouacs each night isn't possible, I think just trying to arrange for more information for the people already there is close enough. Think about how significant a few tweets from Team Dakar GB racers were. Just getting the people already on the ground there to share the information at their fingertips seems like it would provide bang for their buck. What if Team F5 bought a rider (or support person) a GoPro camera & data card and gave them a way to get the the data relatively easily? Could we get Scotty Breauxman to do our bidding? Maybe we could talk SpeedEnergy into doing some coverage on the bikes (they put together some great videos on the cars!).
But that's the challenging part: how to get photos or video back to the U.S. via the interweb when that's a lot of data to upload. (Having Ted there solved the problem for this year's Dakar, as did Neil there in person). Twitter pictures helped a lot too.