I have my MD resident, and a PA non-resident, CCWs. I live less than a mile from PA, so I got both (mainly for reciprocity - NOBODY recognizes a MD permit).
I have family in FL, and drive to visit. I plan - next time I'm down - to get a FL permit as well, so I have the whole east coast covered and can drive worry-free. But...SC is a stickler and it looks like they only honor resident permits, not non-resident. I guess I'll have to ask about claiming 'resident' status in FL, since I have a family address there...
For my PA non-resident though, I simply showed them my MD resident permit (they were amazed it even exists!), filled out a form, paid $20 or something, posed for a photo, and walked out with my permit. No live-fire requirement since I did that for my MD permit, and it is an active permit still in effect.