I used to live in Santa Cruz and have ridden (and toured) all those roads extensively.
I highly, highly recommend a loop south through Big Sur over to the pinnacles. I described the route I took here:
Touring the California Wine Country
This route has one unbelievably hard but exceptionally rewarding climb - Nacamiento Road. Be ready for many miles of steepness. The nearly-undeveloped camping just over the top is very nice. Bring a way to purify water, there is a stream but no tap water. If you do it in spring, be prepared for really beautiful wildflowers.
I imagine the northern route you are talking about includes Big Basin State Park. THis area is very nice, hilly forest. I think the southern route is more spectacular, but if you love big trees, hilly riding and little mountain roads in the forest, you'll like this route.
I don't love Highway 9, it does carry a good amount of traffic and the shoulders are not very big. Ther ei s some commute traffic in both directions, from the little mountain towns to SC and San Jose.
People do ride it, but it is a little nervy. There is an excellent back-way from Santa Cruz to Felton via Scotts Valley - from Soquel Dr. in Santa Cruz, head up Branciforte, and then turn left after the park at Glen Canyon. Turn left (still on Glen Canyon) at the stop sign in about 6-8 miles. This takes you up to Scotts Valley. Make your way to turn right on Mt. Herrmann ROad, take that Felton. Then you encounter Hwy 9 above the Santa Cruz - Felton commute corridor, and there is a bit less traffic. This route adds some milage (maybe 5-10 extra) and a small amount of climbing vs. just starting up Hwy 9 at the intersection with Hwy 1, but if you have time, it is a very pleasant way to get up there. Alternatively, there is a frontage road along the north side of Hwy 17, which works just fine and is safe, but just isn't as nice.
If your goal is Big Basin, you do have to ride on 9. The other thing you could do is approach from above, and descend 9, which will put you on it for less time. That whole little loop road (236?) that goes to Big Basin is great, both above and below the park. There is a store in the park.
If you want to descend 9, there is an absolutely awesome road that leaves Scotts Valley at the north end of town, off Granite Creek, called Mountain Charlie, which takes you up to summit road. It has 3 evilly steep sections, but they are short. You will want either a very light load or low gears.
Coming into SC from the north on Hwy 1 is just fine, lots of shoulder, no issues.
Felton Empire is good.
Empire Grade is good.
Smith Grade and Ice cream grade are good.
Note the use of the word "grade".
You do NOT want to ride Jamison or Alba with a touring load, unless you like multiple miles of 18% grade. Zayante is also really steep.
Leaving SC to the south, the Kirkendall & Spring description is fine, there is some not-that-inspiring riding, and there are some nice detours available, but they are a little complicated to explain.
If you are riding from San Jose, I posted something not too long ago about a route from Saratoga to Santa Cruz, here (several posts from me in this thread):
Considering riding from Los Angeles to San Francisco. Advice, routes, etc?
Look for the Krebs map for the bay area, that gives you a lot of information.
Have a great tour!!!
(And if I haven't bored you to tears, and you want more info, feel free to ask.)