Driving to Green Olive Buffet & Grill is like entering another world. The restaurant sits about halfway between Old Town Alexandria and Mount Vernon, an area little known to most Washingtonians. A 30 minute drive from downtown D.C., this stretch of Old Richmond Highway is a mix of newly developed shopping centers, chain restaurants, and relic motor lodges advertising vacancies and modern conveniences such as A/C and free HBO. That and the best old-school Chinese/American…