This is hard to do in California. It's hard to not go the speed of traffic. From S. Ca to N. Ca there are only 2 lanes and going 65 would mean I'm going slower than the truckers.
If you really feel that it would be unsafe then I understand, however I have rarely been in a situation where going five miles over the speed limit in the right hand lane is unsafe or creates any type of major disruption of traffic flow. Sure even in the right hand lane I sometimes have someone get on my tail because they want me to speed up. Usually it's because they have an exit coming up in a mile or so and they don't want to go around me. But in some of these situations I will pass the next exit but they continue to stay on my tail, so it's just a case of someone who is just habitually aggressive and expects people to get out of their way, which in most cases probably works for them, just not with me, especially if I am on cruise control I just leave it and keep going the same speed, they eventually go around. Trucks I am more lenient with as they cannot change lanes as easily, but if there are no other cars around preventing them from changing lanes then they can go around me also.
Now if there are only two lanes in each direction and there is so much traffic that it is difficult for people to go around me, and I would be literally causing a slowdown, then sure I will accommodate, but that is extremely rare, and it's hard to imagine that it is like that the entire stretch of I-5 from southern to northern California.
Don't get me wrong if you want to go 75-85 I have absolutely no problem with it. And I am not going to try and pretend that I never speed. I am just generally skeptical about claims that it is impossible to go the speed limit or "I'll get run over". I know that's not what you are saying, you are saying it's hard. I guess sometimes it is, and it's been many years since I have driven on that section of I-5 so I am not going to question your experience with it.
Funny thing is, one thing I have to live with driving in the right hand lane is dealing with a common habit that many people have which is to start slowing down well before their exit, oftentimes slowing below the speed limit when they still have half a mile or more to go. It's just some unconscious habit that many people have. Many times there will someone going well over the speed limit in the next lane, they pass me and then pull in front of me, and then start slowing down so then I have to cancel my cruise control so that I can stay safely behind them (no I don't tailgate them). Although now with radar cruise my cars slows down automatically so at least that helps.