Did that last year, camped on beaches and parks when could.

watch for stacked rocks! They're everywhere (in the remotest parts of nowhere). I dunno who's stacking em, but I ran across about 2 dozen.

Lots of altitude, climate/temp changes very fast - light layers needed.
get superlight rain jacket (stretchy kind, use as light jacket)
waterproof hiking shoes/boots
in seattle, pick up down vest at "feathered friends"

(glacier national park, yellowstone might be on your way. There is a national park pass for like 20bucks good everywhere. (got snowed on this time of year at yellowstone)

seattle:
gum wall (by pike's market), troll under the bridge, waiting for the interurban (sculpture the locals "grafiti" for holidays, protests, whatever). First starbucks.
Also, Seattle underground tour (town used to be one story lower), lots of history, deadly toilets and such. The namesake of Skid Road is downtown, where they used to slide all the timber down (poor people lived there)

Cross puget sound and go north around to the pacific - fantastic country down to OR. Watch beaches change from Olympic WA (western most point has a RV park by the indian res that will let you camp on the beach), to Imperial Beach in San Diego.

Hoh rainforest, the only rainforest in US over there.

Be sure to eat as much fresh fish/crab as possible, till you get LA and lower, switch to mexican...... mmm... fish tacos Lots of hole-in-the wall fish places to get smoked salmon instead of a candybar for a snack.

Oregon
did beaches mostly, cool dunes
portland has the worlds smallest park:"Over the years, items have been added like a tiny swimming pool and diving board for butterflies, a miniature Ferris wheel and more."

at the very SW corner (near cave junction), there is an "ewok village", a bunch of treehouses you can rent. multi-story, 40ft up, rope bridges, bonfire.. awesome. They have a zipline course you can take in the morning.

N Cali
Jededia Smith Redwoods state park was coolest park - think land of the lost. Avenue of the giants is another, i think they have a tree you can drive through (there's a few).

Bohemian grove is up there (secret society retreat)

Nappa and Sonoma wine country is truly beautiful. (tell them you're buying a bottle - they'll let you taste for free)

San Fran: i dunno, tons. I want another crab eggs bennedict at the cliff house personally.

LA. Start of real mexican food. mmm...

Gamble on some horses in Delmar and hit the fun little ocean towns on the way down to san diego. Dont take the 5!! take the pacific coast highway. Sure it takes forever, but you've got time!

San Diego:
Glider port (Torrey Pines?, north of LaJolla) big cliff hangliders/parasailers like to jump off. Bring bonoculars, its above Black's beach (nude). Famous modern architecture building.
LaJolla has "munchkind land" (most is gated now, but you can get there if your sneaky). There's the beach full of seals (and seal's poop), but there's also a hidden on used to go to all the time, tourmaline or something. From there you can walk around beneath lajolla cliffs and its just you and the ocean.
Pacific beach probably has the most "baywatch" style beach.

Downtown there's a parking ramp that's built too high. Sit on top and watch the airplanes come in and read the writing on the landing gear tires. Its a thrill.

I think you can tour some of the military ships, I got on an aircraft carrier while they were in port. Amazing.

there's the cross (good view)
point loma has 360 panarama lookout.

Nearby on rosecrans, they'res Albertos Mexican food (California burrito has french fries) God love em.
Rubios - famous for fish tacos

Ocean Beach is over there, fun throw-back to the 60's kinda vibe.

Then it gets crappy down imperial beach to the border and TJ.

Vegas: yeah baby. I'd give you some spots, but its all bit hazy.

Utah: Zion is a short hop from vegas. A must see. I missed it, but heard bryce is good too.

Arizona: Another short hop gets you to the north rim of the grand caynon. Its more rugged than the south, less toursty.

The drive down to Flagstaff thru reservation is remote and majestic, like you're driving through a picture.

I had to get back so I bypassed em, but there's a petrified forest, rosewell, sedona (psychic vortex or some crap - hippieville), labrea tar pits and roswell.

The joy is in the places between places. Seriously, No fast food! It'll force you into all the diners, road side shacks.

I'm really not kidding about the rock stacks.

Have fun!!!