OP, I would check the Hertz website for any specials, including PC to go with certain CDP codes like AAA - and, compare rates for different category of cars, as you might find a better deal on a full-size or even mini-van vs. a mid-size/std. based on your travel dates (flexible)

Coming down from SEA, you might want to look into spliting up the OW by returning at SFO, and, then book a 2nd. one between SFO and SAN to see if you can find better rates.

I have an upcoming one-way from LAS to LAX, booked about 6 weeks ago - under $400 all inclusive, unlimited miles for a 7 psg. SUV for a week's worth of driving around. The std. SUV rate would've been about $75 less & not bad - but, going the opposite direction, from LAX to LAS would've cost upwards of $700 for the week. Picking up and returning at LAS would run almost the same for these SUV ... interesting, huh.