Just my $.02...From a local point of view, no, it's not hard being the only local on campus. When all of the sororities on our campus decided to go national in the early 1990s we were the only one's who decided to stay local. It was just the right thing for us to do.
Over the last 7 years that I have been around we have almost always been the largest group on campus, we have the highest retention rate of new members, and our alumnae are much more active than any other alumnae groups.
Best of luck to you!!