Well, since most people who travel to MB and go the "Rockingham way" know how to get to Rockingham, I will only post from there. I didn't put these under OH, Pa or anywhere else, you already know who you are.

Everybody has their favorite way and miles vs time vs interstate vs off the beaten track. I'm not going to debate that again here, I just wanted to give the routes we took and the ease for which they provide an access to the beach. We've taken this route back TWICE now from the beach and just really like it...it's easy.
From Rockingham:
I74E to Laurinburg. Stay on I74 and don't take 74business at any time all the way to Chadbourn. At Chadbourn you will pick up 410S to Tabor City here you will pick up 710. 710 runs right into Route 9. Take Route 9 to 31S (& 22) if you are headed to MB & South Strand.
Of course, you can stay on 9 if you are headed to Little River, etc. You can also take 31S to Main St Connector now, I see on the map if you are staying in NMB.
Honestly, I would still take this route if I was going to the Southern Strand as it goes all the way to 544. 31 is an awesomely unused road. JMHO
We took this route back again this time and made it from SeaWatch to just past Wyethville in 5.5 hours. That's pretty good time. Only a few places for several miles is it a 2 lane route.