I think that a carbon road bike is an excellent choice even for a self supported cooking and camping trip if you pack very light. For me at least, and for a supported trip the touring bike wouldn't even be considered.
If you usually ride in flat country, you may want a bit lower gearing than normal and maybe, but not necessarily, slightly wider tires. Basically I'd take whatever bike I'd ride if I was doing day rides in similar terrain. I would probably just use the 23mm tires that are on it, but putting on some 25mm wouldn't be a bad idea. On my road bike 28mm are a bit tighter fit than I like. If a wheel gets slightly out of wack a little extra clearance is nice, so I avoid up sizing to the max.
I did the Southern Tier on an older (1990) Cannondale Crit bike with 23mm gatorskins for the first half and when they wore out I put on 25mm gatorskins. Gear and bags were 14 pounds, not counting food, fuel, and water. The bike was an OK choice IMO, and the 23mm tires were OK, but the 25mm ones did reduce the buzz on the Texas chip seal quite a bit. I think that a carbon road bike actually would have been more comfortable.
The question may be, how comfortable are you on your carbon bike. After doing a few centuries around home one Fall using different bikes, I found that I felt better not worse after the ones where I rode the road bike.
