Trailers are only useful if you need to haul more than one car at a time.
Small japanese trucks are what us pro car hoarders use.

Look at renting an enclosed Pantech 3 tonner. Drill some holes in the floor to mount some eyelets for tying down and if the car is too long remove the rear doors. Disconnect the speedo sensor so you don't get slugged the KM surcharge and run a GPS for your speedo. A small Jap truck will use less fuel than a Falcon towing a trailer and the new ones are nice to drive on the highway. Big spacious cab that you can really fill up with roadtrip shit and upright seating position limits fatigue. Some extra cushioning on the seat can't hurt if you'll be doing 8000km.