I did Dallas to Fredericksburg down 281 last weekend (
Here) and from a comfort standpoint, it was just fine. At 6'4" - 250, I'm a big guy, but was pretty comfortable the whole way.
What was a big draw back was the road noise on some of the lesser highway pavements. I realize I can probably help solve this with some different tires (Hankook v12 evos seems to have a good rep for performance and ride balance) and sticking to more major highways, but it was really loud over some of that rougher pavement out in the country. With the wife in tow, it will be the road noise that is the limiting factor, not comfort.