Definitely tthe northern route. I would recommend Highway 19 the whole way. Your one choice would be to take Hwy 190 (Palani Road) from Kailua-Kona, but for the most part it's a very narrow road and you really have to pay attention the whole time. Not a good choice if the driver also wants to enjoy the scenery! Hwy 19 north of Kailua-Kona is a much wider and safer road. Just a few miles longer. Maybe stop for lunch in Waimea?
Sunset in Hilo in late January is right after 6 p.m., and if you want to get there just a bit before that, and considering a total driving time right around three hours it doesn't give you much to play with, especially if you deduct an hour or so for lunch. Unless you want to just grab something and "eat on the road".
Two possible little side-trips:
Waipio Valley lookout (from Honokaa head north until the road ends). Verry scenic. Max one hour for the entire detour.
Akaka Falls (heading up a couple of miles from Hwy 19, right around the 12 mile marker). Including the drive and a relaxed walk you're probably looking at 75-80 minutes for this detour.
One other stop that doesn't involve a detour, but it's pretty spectacular. On Highway 19, coming from Honokaa, you'll be driving across a number of bridges over deep gulches. There's one bridge, but I forgot if it's right after the 20 OR 19 mile marker (coming from Honokaa). You;'ll be driving across a fairly long bridge, and as soon as you get to the other side, there's plenty of parking space on the right side of the road. Pull over, and then walk halfway out across the bridge. There's a narrow sidewalk on both sides. Very dramatic scenery. There's no other bridge along the way where you can safely do this, so don't pass it up thinking you'll get another chance!
Edited: 14 years ago