I've got another couple of questions. First, how long do you have to wait before they settle and you can re-open the hive at the new destination? Second, can I move a hive where I've got a new queen? I mean a queen that maybe has not mated yet. Thank you.
How far exactly is this new site? if only five,ten miles then an OMF should be sufficient (as long as you're confident there will be no serious traffic holdups)
Seal the entrance up the night before and move them first thing in the morning (so it's still relatively cool) use at least two hive straps either at ninety degrees or parallel one to each side - this will stop the boxes shifting and twisting apart.
Orientate the frames so that they are running fore and aft to the direction of travel (Frame lugs pointing to the front and rear of the vehicle), maybe raise the hive a few inches off the floor to ensure free movement of air.
To be honest, I just open up as soon as I put the hives in the new position, unless you've been particularly clumsy in moving the hives you shouldn't have a problem. Then again, had one hive fall off the barrow and roll twice before stopping at the new hive stand, I opened up immediately and still no great fuss.
If you have an old net curtain or mosquito net, drape that over the hive in the car and always keep your beesuit handy.
IF you can, I would wait until the queen is mated before moving, but if you have to - I can't see it being a big problem.