Hello and welcome to the RTA forums !
If it's the coast you want to see then travelling on CA 1 and 101 is the way to go. There is much to see along the PCH and you will find lots of info using the search button. Driving around Big Sur and a Hearst castle tour are very popular. You could take a straight shot up to San Francisco on I 5, have a day there and spend a couple of day's coming back home on the coastal route, depending on how far North you want to go.
By heading South down the PCH all the sea views will be on your side of the road and is recommended.
As for the weather, keep up to date with forecasts using a site like The weather channel.