Agree. It is reasonably safe. As said earlier, Oregon is very bike friendly. Nice shoulders. Accomodations are easy to find, particularly at the time of year you are considering. California roads do not provide the same type of shoulders but I still consider the ride as "safe". I do use a mirror and I am aware of what is coming up on me.
As to climbing - I consider the short climb out of Charleston (Seven Devils Road) as strenuous but there is no rule that says you can't stop on the ascent for a break. The climb over the Crescent City Hills south of Crescent City is just long and, again, minimal shoulders. A number of climbs in Oregon, as you would expect, but nothing out of the ordinary. As I thing about it, if you take the Three Capes Scenic Route (I do suggest this alternate) there is a rather steep climb. My gearing is rather low because after a number of trips I decided I would rather have low end gears I do not use rather than high end gears I will never use when touring. The descents can be exhilerating. On one of my earlier trips, on the descent from Cape Sebastian I reached 53.9 mph, and the whole time I was thinking, 'this is sooooo stupid'.
In addition to the CGOAB site, the Tom Kirkendall and Vicky Spring book, Bicycling the Pacific Coast, is a good guide. Oregon has a specific bike map for the coast trip. You will likely find that very helpful. California does not have a specific map (at least I haven't been able to find one).
A final thought - whenever an alternate route is suggested that will take you off of 101, take it. I have never been disappointed.
If you are thinking you will take a month for the ride, you should have an incredibly enjoyable trip. Plenty of time to stop and enjoy the coast and the redwoods.
My best to you.