The big difference between my upcoming trip and my last one, aside from the fact that I will be a coddled cruise ship passenger traveling through Alaska rather than a muddled driver wandering through the southern United States, is that I won't be traveling alone. Megan and I have known each other since high school and we've traveled together once before, to Ireland two years ago. So I know that we can go for extended periods without getting on each other's nerves and neither of us snores, which is what you want in a traveling companion. Our only source of tension was driving- always problematic in places where people use the wrong side of the road. I ended up doing most of it, which was apparently a bit stressful. You see, though a northern Californian to the core, I had my formative driving experience in LA, which means that I take to the road with the firm beliefs that: 1) 'speed limits' are really more like suggested minimums and 2) I have the right-of-way. (I would like to point out that I have never been involved in a major accident.) But anyway, the opportunities for driving while on the cruise should be pretty limited, so I expect we'll do fine.
(On a related note, I want to offer the advice that, while two people can do great on a trip, and four or five can be a blast, you should avoid at all costs traveling in a group of three. Just trust me on this one.)