I'm not related to any Walker's in SC, but here's a couple of options:

1. In the days before the internet folks just broke out the phone book and called. Try ordering the phone book from the particular area you want (or go online) and look up the folks with surname Walker. Write some letters to them or simply call them. If they're not related or have no info, no harm, no foul.

2. Try a public record search on Ancestry.com or people search on Yahoo to get phone numbers (to call), street addresses (for snail mail) and/or email addresses.

Option #1 helped me locate my dad in IL before he died. Good luck!