No matter what the format, the wife and I plan to participate! We greatly enjoyed meeting ofreen when he handed PZ off to us and also EnvinoVeritas when we handed off to him. Two completely different dudes with much different bikes but both were awesome! That's what it's all about IMO. Meeting great people who share a mutual interest.
If it is decided to split the country in thirds, I could see it starting in the south, heading north and then back south again. It could be cool to have the southern starters begin at the Mexican border(or gulf/ocean depending on geography) then relay to Canadian border and back down to Mexico/waterfront.
I realize that most of us are only referring to the US. What about our members in Oz, UK, Europe etc? What can we do to run with multiple lizards in multiple countries and still have some larger sense of community? Maybe a monthly photo contest or monthly photo album compiling global pics? It's pretty easy to make a slide show on a computer these days.