+1 on Foothills Paddling Club. Get in touch with Mark on the FB page and let him know what you're interested in running. There's also an email list that posts multiple runs per week in the summer.
In the off-season, start showing up at the Westside Aquatic Center roll practice, which runs on Wed evenings from 7:30-9PM (cost is $7). In addition to practice, it gives you a good opportunity to meet local paddlers and set up trips during the season. http://greenvillerec.com/parks/westside
Also, Sunrift Adventures in Travelers Rest has a good selection of gear, and knowledgable staff (I have no commercial interest in Sunrift). They can get you in touch with the right people, and they typically host a bonfire party around Christmas behind the shop. http://www.sunrift.com
Welcome to the area - feel free to PM me with any questions.