Best web resources for planning roadtrip from WA to CA?

I know this is probably one of those projects best served by actual human, lived experience, but I’d really like, for my own peace of mind, to be able to find out where I’m going to camp or stay in motels on my trip from Seattle to Sacramento. Any guidebooks, maps or online resources that you’d recommend would be very helpful, as would any information about hiking in the northern Sierras. Thanks much!