I relocated to Charlotte back in 2001 from Downingtown, PA, when I worked with Vanguard! You will love getting away from those Nor'easters, no doubt.
To answer your question, it really does depend on your individual circumstances. As others have already told you, some lenders require a rental history or at the very least, a signed rental agreement before they will consider your house in Philadelphia as a rental. Here are a couple of thoughts:
1) Do you have a lender in mind? Allen Tate Company has a very large market share in the Charlotte residential real estate market. We have our own mortgage company, and I can put you in touch with one of our mortgage professionals for a no-obligation consultation. He'll be able to give you some ideas on how to finance the purchase and what you might need to do in order to get approved to hold two mortgages.
2) Do you have a property management company in Philadelphia that will be managing the property for you? If not, let me know where the property is at, and I can put you in touch with a Realtor that can manage the property for you. I have rented out my personal property in Charlotte at one point when Vanguard transferred me back to Malvern, PA. You really need a local property manager that can take care of any issues with the property or the tenant. I could refer you to someone if you do not currently have one in mind.
3) Would you like me to send you a no obligation relocation kit? This kit would give you some information on the various amenities and their locations in Charlotte, and will help you begin to figure out where you might want to live. Whether you are able to buy or need to rent down here in Charlotte first, I would love to help you. I can assist you whether you need to find a home to purchase or a place to rent. Just call or e-mail me.
Welcome to Charlotte!
All the Best,
Allen Tate Company