Let me clarify what I said. First saying this is a big country and I assume that if you are transporting bees in Texas that it is probably pretty warm. I like venting at the top and entrance to cause thru-ventilating if it is very hot and during the day time hours.
If it is night time, then surely you don't need to go to that extreme of screening the top UNLESS as Trail Twister did, as a safety feature. If it is cooler than hot, no top venting should be needed. But it can get mighty hot in Texas according where you are driving 330 miles to. If it is South of the state and laterally across the state, it could be really hot. A vertical trip could be like driving from here in NJ to Maine - trust me, we do not have the same weather here as Maine.
If you are in constant traffic, fumes could build up in the bed of a truck and draft behind the truck may not be as "windy" as many assume either. Again, fumes or hot air could get trapped in the bed.
My whole point is, the more info we have, the better we can all answer a question. Personally, I like nucs - think they are really cool for starting up a hive. But I am amazed at how far people will drive to get bees. I remember Trail Twisters adventure which was amazing to me - but 330 miles - WOW!
I never ordered nucs, I built them and have given many away for pollination to family and friends and to people wanting to see if they are comfortable with honeybees. But I have never ordered them, I have had every package delivered at my door except one time I drove 1 mile to the post office to get them.
It's a big big Country folks - even here we get and process our bees very differently - you do not have to go abroad to see differences in how we enter and manage this hobby. That is what makes beekeeping so fascinating :D