Feel free to google the maps of San Diego and take a look at the various canyons that block parallel roads.
No problem, I'll wait.
In one area the freeway is actually open to cyclists, as it provides the only direct access to a northern canyon that is used primarily for light industrial. There are parallel routes. Both are mulilaned arterials marked at 50MPH... so the choice is 70MPH or 50MPH. You chose the alternative you want.
Where I live, there are only two roads that cross the canyons and freeways... period. The only roads that go north (I work north) out of where I live are 45MPH, 50MPH and 65MPH respectively, and two freeways. Chose your alternative. I usually use the 45MPH road. It only has 6 lanes. (3 each way). No one drives 45MPH.
As I wrote earlier, I don't doubt there are some people who have no other choice. If you feel the best way to deal with high speed traffic is to place yourself in front of it, then you do what you think is best for you -- but bear in mind that you have a relatively unique situation, and even in your situation, there are extremely experienced and knowledgable cyclists who would not do as you do.
I will go as far as to say that I believe "VC" has some intelligent points -- but the attitude that it is always right for all cyclists in all situations (not that I am saying this is you, genec) is demonstrably false, in addition to being fairly obnoxious.