5 hours is a mid range drive as I used to commute 3-4 hours daily. Its about my trip to LI from DC. What I usually do is bring a traveldor with me with a variety of smokes and this way, I can have a long or short smoke depending on mood. I've smoked 2 and I've smoked 5 on that drive. For the most part, on longer drives, I like to smoke something in a toro or corona gorda size but nothing much longer. You can always smoke something like an A but they tend to get boring on a long drive. The real fat guys ie 52 ring and up make a lot of ash and the real thin guys tend to burn unevenly with the wind so I try and stay around a 46-50 max. Good thing about my route is that almost every stop along the way has a Starbucks so you can always recharge. Bring good tunes, a variety of smokes and a couple of red bulls and you'll be set. G1
Goalee1 hit the nail on the head, I used to do cross country runs for my old job, and a traveldor is the best way to go. If you don't have one, take a gallon size ziploc bag, throw a mini humi device in there and chuck as many sticks as you want in it. My traveldor gave up the ghost just yesterday, and I use this makeshift one, along with a hygrometer, and it's holding perfect %'s. Just be careful with them, unlike a traveldor, this won't protect them from getting banged up, which is why I throw the whole thing inside my old traveldor, heh.
As far as which smokes, I'm not sure what your tastes are, but definately not something too strong. Strong cigars induce two things you don't want on a long trip, lightheadedness and bathroom breaks, so stick to your favorite medium smoke, throw on some tunes (Or, my favorite, the original James Bond books on tape), set the the cruise control and enjoy yourself.
One other tip, bring cigars that you know are very well made, it's a pain in the ass having to worry about the ash constantly falling off, where as it's peace of mind to know the one your holding will last over an inch before you need to take care of it.