Chico,
There are a number of reasons why Fort Mill/Rock Hill kids choose to play in North Carolina. I have a U-14 daughter playing there now. One of the prime reasons she is there has to do with South Carolina scheduling (related to our geographical proximity to NC).
We get quality competition there at the classic (SC challenge) level without having to drive all over the place. When we were Northside (same for Discoveries and Tega Cay) we were lucky if we got one home game. All other games we went south to Greenville, Lexington or Columbia. My U-12 daughter, who does play in SCYSA, traveled three times this season to Anderson and Aiken.
In NC, we get half of our games at home, less than 15 minutes away at the Ramblewood Complex. We may have to go to Greensboro once and to Asheville once. Most of the teams are actually in Mecklenburg County (Charlotte). Also, there is only one game played per day (usually Saturday) which is nice.
