If you do not have any sort of license/permit from South Carolina, or any other state, you cannot transport a firearm in a vehicle in Pennsylvania, thus you can't open carry since you can't get anywhere to open carry without being in a vehicle (which requires a license/permit).
Why haven't you gotten a license/permit from South Carolina?
Statkowski, I'm sure you know better... you're just being too vague and someone's likely to get the wrong idea.
I AM NOT A LAWYER.
You may transport a firearm in a vehicle in Pennsylvania without a permit... it must be unloaded and in a secure wrapper. The link below goes to PAFOA's web site which re-printed the PA firearms laws. You should read that entire law, as well as the other laws regarding firearms in PA that are conveniently linked from that page:
18 Pa.C.S. § 6106: Firearms not to be carried without a license (subsection (b)Exceptions(8) and (14))
See the Federal laws referenced in (14) to details on the interstate transportation. Basically, though, you may transport firearms unloaded in the trunk (or if you don't have a trunk, in a locked container in the passenger compartment, from one place to another provided that you may lawfully possess those firearms at both the origination and the destination of your trip.
So it's your choice: either transport in compliance with federal law, in compliance with state law, or both. Pennsylvania law regarding the transport of an unloaded firearm in a vehicle is more lax than the federal law as it only requires that the firearm be unloaded and in a secure wrapper... I can't legally define a secure wrapper, just use common sense. I'm pretty sure that a plastic or soft gun case (zipper or snap close) is a secure wrapper. A towel or sheet is probably not a secure wrapper; but maybe if you wrap it with said towel or sheet and secure it with duc'k/t' tape... don't take my advice, though... do your own research and make your own decisions about how to transport the firearm while in a vehicle.
Pennsylvania does issue permits to non-residents (as long as you go to the right county) and it may not take very long. Allegheny county, by the way, is one of the few counties that will not issue permits to non-residents. Being a non-resident, you can use any county you'd like.
Other than that, open carry away except in prohibited places. opencarry.org and pafoa.org, the latter being more thorough when it comes to PA, will have all of the answers for you regarding where carrying is off-limits as well as the information contained in this post... just be aware that OC'ers are a minority in SW PA, so chances are there will be some negative encounters.
Let's see if I can answer your specific questions:
So I was wondering what about travel? Do I need permits? Do I need to keep my weapons visible like here in NC? Do I need to lock it in my glove box like when I am back home in SC? What must I do to not scare some rookie cop. Or end up explaining myself to some salty officer?
I think I already covered the travel... and permits... In order not to scare a rookie cop, or anyone you don't intend to scare for that matter, DON'T TOUCH IT; don't readjust the holster in public. When you're speaking with a police officer, I recommend placing your strong arm across your abdomen or crossing your arms in front of you. You also don't have to explain yourself if you don't want to do so. You have the right to remain silent at all times.
I always try to be nice and calm when dealing with people, especially when they are not being nice nor calm; and show them the same respect that you wish to be shown. Belligerence is threatening to some people and tends to only escalate a situation.
I am from Pittsburgh, though I live in Virginia now. Let us know how your trip to the Burgh goes and please report your OC experiences here.
Thank you for your service.
<edited to correct statement about Allegheny county>