So I just drove straight through to California. 12 hour drive-my wife and I alternated driving all night/morning.
I am licensed to CCW for the majority of the trip until the CA border. So I will be darned if I am going to travel across multiple states because one state is ridiculously restricted. I will meet their requirements for that portion of the trip.
Just before the border my 9 shot pistol (Glock 27) - I didn't want to bring a CA restricted/banned mag since I dont know what the ramifications are - is unloaded, separated from the magazines, locked in a hard case, which is then locked in the trunk. My trunk has a "pass thru" so it is in its own lock box so there no question of it being "secure" (CA definition).
Anyway, I had my Glock 27 strapped to my ankle in a Renegade Leather Holster (great holster by the way). 12 hours? Not a good idea. Not comfortable, in fact hurt my back. As a matter of fact when the little Glock got packed up from hurting itself (per CA law) my back felt better! Definitely not carrying on the ankle back. Good thing I brought my Maxpedition Versipack bag.
I am a big proponent of shoulder holsters for driving but not when it is 95 degrees out. People at gas stations and rest stops look at you funny for wearing a cover garment. Still, if you have AC it is an option. I will have to get one for my Glock 23 and see how comfortable it is. Oh, and I guess, some 10 round mags for it too.