Many divers on Olympus want to dive the sub. After factoring in weather conditions, the majority on the boat typically will pick the spot that the Olympus or Midnight Express will go to. So, if you are coming down to Morehead by yourself, or with a buddy, you may not be the majority, but you may be in the company with a group(s) that wants to do the same dive. It's good, and well worth going to to see a real piece of history like the U-352. After you get that dive in, and you see the sub (it's smaller than you think, and you can easily see the entire wreck in NDL's, on one tank), go to the Papoose, the Shurz, the Naaco (far offshore), and many of the other offshore wrecks there. You will see that they are as good or better than the sub. But, like most others, I HAD to see that U Boat. I've been on it many times, and only really enjoy it now when I dive with someone who hasn't seen it.
If you can fill a six pack, take ScubaSam's advice. I have not been on Tortuga's dive boat, but am planning it for 2011. There is nothing like chartering a boat that will hit all the spots that you request.
Bear in mind the weather again. It has to be safe to go 30 miles offshore (the captain is thinking about the run out, the dive time on two wrecks, and the run back - The run normally takes 2 hours, oneway). NC can be rough, and I've spent many dive days bouncing around. But we have also had great dive days, flat as glass and maybe an occasional roller or two. It's a crap shoot. I understand your concern about driving from Missouri, that's far (but still worth it). I drive from north of Philly, and it's still far. But the diving, and the southern hospitality is all worth it. Have fun.
Safe diving to you.