Bike or car book and residence letter from immigration. Go to immigration with condo rental agreement, or blue house book if with wife, 2 photos, passport and it's done. I think valid for 1 month. Take those to land transport and fill their forms to transfer the vehicle.
Just be careful of where you do your exit entry. I used Aranyaprathet and got a lecture from the big boss about can only do once, next time have to fly. Made no difference to her that I have a 1 year non O multi entry. I know that border is a complete piss take and they make their own rules up.
Agree, don't use DHL. If you absolutely have to ship your stuff, using a handling company like Asian Tigers to do it. Avoid fedex and DHL, will cost you a fortune.