If you take I-5 and decide to go to the redwood forests (Fortuna area), be aware that if you take SR-36, it is a very long road and you will have to take the whole thing.
At the beginning of the road, you will see a road sign that shows an "S" curve and then a sign below it "Next 140 miles". Just make sure you have a strong stomach.
Also, as of a couple of weeks ago, the rim drive around Crater Lake wasn't fully open (or even 20% open). You might want to check with the park to see if it is fully open. It is an AMAZING park to see.
(PS: I have tried to attach the picture of the road sign, so you see what I mean -- I hope it works).