Whilst not a great help to you I thought I'd mention that whilst importing some cars from the UK to Canada I noticed that I had the option of routing the container to Vancouver which might be easier for you being west coast. Second thought; the transport agent I went with, MJS, Helicopter Shipping & Vehicle Transport from MJS
, Martin deals with exotic cars, helicopters etc and may be able to help you out. I have seen Airstreams shipped in the oversize sea cans so maybe that would work for you as once it's in the "can" transporting it is a bit more of a known quantity.
I notice your in Penrith which reminded me of one of my favourite movies, "Withnail and I". Hope your trailer has a safe journey.