When I started training for racing in 2008, I used a coach that used the climb up 84 versus OLH quite often in the early part of the season. The reason is he wanted more speed for less effort and then we continued to the coast and returned via 84. Later when he wanted more mountain style training we started at Canada / 92 and climbed OLH and descended 84 and left to Pescadero. Right on Stage to PCH and then right on Tunitas Creek to the top of Skyline and descend Kings Mountain.
We climbed 84 in the morning and traffic did not seem to be a problem. I was in NorCal for 16 years of cycling so situations may have changed since I moved in 2016 to SoCal.
There is another interesting climb that may be a good workout for you that is shorter. It is Crystal Springs to Highway 35. At the juncture of Crystal Springs and Pulhemas bear right on Crystal Springs. The climb is about 3 to 4 minutes to 35 but not too steep. The descent is easy and safe. Do as many reps as makes sense.