People always told me I should have gone north to south, but I made it (to Seattle), just fine. What kind of route are you taking? The Coastal *is* gorgeous, but has some treacherous stretches. The traffic on most of it is very light, until you get to Leggett, CA (and you're then forced onto the 101). The extra scary part is once you get onto the 101 (headed north), you have *no* shoulder while passing through Richmond Grove and the likes. It's only a few miles, but there are trucks and such. That's the worst part of the trip, in terms of road conditions. The scenery is to die for, and write home about. If you are taking the Coastal HW, exit for Avenue of the Giants as soon as you see the exit for it. There are a ton of elk in the area - a few herds are known to hang out right off the highway. I got to experience a close-encounter with them, and it was both hilarious and frightening.
Camp spots are hit and miss along the coast, I found. Until you actually get into the Redwoods, it's mostly private land all along the coast. Then you turn east into the forest, and while a lot can be privately owned land, a stealth-outing for the night won't be a problem. The campgrounds along Avenue of the Giants are definitely a sight to see, though, I'm afraid this time of year they will cost money (I rode it in early Spring / late Winter, and the camps were all closed until June or so). There are morel mushrooms to be picked throughout the Redwoods, if you're into that sort of thing. I picked one larger than my hand that weighed in around a pound. Prepare for bears once you get north of the Bay Area (SF) - this means you need to be mindful and not eat food in your tent...the whole trip. I'd suggest hanging food / smelly stuff once you get north of the Bay. I didn't, and nearly regretted it (just outside Crescent City).