I use the 15 north to 210 west to the 5 north, to the 126 which will dump you out in ventura (through santa paula) it is by far the best way I have done, with or without a trailer, also when you come into filmore (on the 126) there is a Vons with a burger king that i always stop at (has a big enough parking lot to get into out of with a trailer) and it has a traffic light to get back out with. you do have to be paying attention when you are on the 210, it becomes the 134 at one point (around pasadena i think), and you have to take an exit to remain on the 210 (unless you do it at 2am there will be traffic slowing for this exit) definately take the truck route to enter the 5 north, otherwise you will have to merge across 4 lanes of traffic in order to not exit on the 14.