Around the time that you're getting bored with expensive beachfront property, you hit urban hell. What is a major highway without a few spraypainted over exit signs. It is in LA where you get the one exit in the nearly 800 miles of I-5 in CA that they bothered to give an exit number to.
North of LA is where you finally (under the old laws) get a 65 zone. The character of the land changes once again as I-5 cedes the Pacific to US 101 and goes inland into the desert. While this stretch is much more bearable than I-15 to Las Vegas, it's still can remind you of jokes about mirages.
When you hit the Bay Area, you get the first sign that things are beginning to change. Around Sacramento the signs about using reclaimed water to water the grass start to disapear. The run up to Redding is quite pleasant, as trees start to become much more prevalent. If you are at all tired though, Redding is where you should grab a nap; the rough stretch is coming.
For the next 200 miles or so, I-5 suddenly resembles Colorado. While the speed limit stays pretty constant the whole time, there are quite a few twists, turns, and slopes. However the real danger is not the mountains we go over, but the one off to our right. Mt Shasta is very hard to not stare at as you drive, but by resisting the temptation you can make it to Yreka and stop at the Yreka Bakery. The rest is needed, because we've got another pass at the Oregon border, and the fog is beginning to creep in.
By the time you hit Roseburg, I-5 flattens and straightens out. When the rain starts in Eugene, you realise that you are in the Pacific Northwest. Deciding not to stop at the college town, you head up past the industrial looking city of Portland. Singing "Roll on Columbia, roll on," you cross into Washington.
Southern Washington state is quite rural. The area is mainly farmland, and the Uncle Sam sign in Centralia reminds you of the conservative politics that the farming community is supposed to have. However, as there is a time to reap and a time to sow, there is a place for farms and a place for cities. It may look like Indiana, but the mountains on the horizon let you know that you are barely south of Olympia. Once you're past there, it's just a hop, step, and a jump to Seattle. While you could bypass the city on I-405, staying on I-5 lets you go right by the Space Needle.
Once north of Seattle, all of the signs start reading Vancouver. While there still is some beautiful scenery and the rather interesting town of Bellingham to go through, billboards for duty free shops and Victoria BC begin to infest the side of the road. After all of that, reaching Blaine is almost anti-climatic.... until you see the backup at the border.