We export from Costa Rica monthly and our main port is in Long Beach where we use the same broker for all our imports. Sorry to hear you had these issues. Our exports from the time we reserve the container (20' or 40' for 2 cars), legal document to unregister vehicle, drop off, load container ourselves and to destination port is anywhere from 3-4 weeks. That's not to say customs controls whether they want to hold the car up for inspection on the US side but all in all we have great success with managing the time and keeping cost low as possible.
Being originally from Texas and have many customers there shipping to the Port of Houston would be great but they don't allow import of personal vehicles anymore. So it's an added cost for my fellow Texans but those on the west coast enjoy going with our broker and collecting at the port. One thing i can't stress enough is having all the paperwork in proper order (INCLUDING ISF) and a broker in the US that knows the system and does the job in a timely manner.