Folks have pretty much nailed the pros and cons of the blog vs. CGOAB options. One thing I would add is that regardless of how the material is presented the result will only be as appealing as the quality of the content. I'm not a fan of the CGOAB "look", but I would much rather read an excellent journal on CGOAB than an average journal on Wordpress. A lot of people create bike tour journals that aren't really worth reading or are hard to read.

I'd suggest you find 3 or 4 journals you really enjoy and pay attention to what makes them so interesting. You'll be ready to record the sorts of details you'll need for a high quality journal entry at the end of your day on the bike as well as what sorts of pictures to take.