I think your best bet is a trip to Sumter National Forest in the hilly northwest corner of the state. Here is a link to an article on GORP.com, with info on things to do: http://gorp.away.com/gorp/resource/us_national_forest/sc/sc_sumt_2.htm. There are also several large lakes near here, including Lake Keowee, Lake Jocassee, and Hartwell Lake, just off I-85. You might also consider the cabins at Oconee State Park or Table Rock State Park, near Spartanburg (visit http://www.southcarolinaparks.com/park-finder/park_locator.aspx for more info on SC state parks).