Need some quick help

I'm not actually a new driver, but this is something I've not dealt with before. I'm planning to buy a trailer next week. I'm in SC and the trailer is in NC. There is no tag on the trailer, and the actual seller will not be there. I am paying for it the day I pick it up, and will only have a photo copy of the title at that point untill he mails me the original. Question is what do I have to do to bring it home. At this point i am planning on renting a Penske tractor to pull it back with.
If this helps, we had tractor trailers, but with the economy we got rid of all of them and have just been running straight trucks. Our trucks are over CDL and we run under our own rights, and we run all over the southeast. Point being is that we have rights to run in other states.
Also if all we are using the tractor for is bringing home a empty trailer just bought, does the Penske tractor need out name and DOT on the door?
What has me confused is the fact it will not be on the road for commercial use, if that even matter.
Thanks for the help