Complex sentence: During this era, Rockville served as a stagecoach stop for those heading west of the Mississippi River, but the hilly area, still traversed by gravel roads, now consists primarily of farms and woodland.
Split into simpler sentences: During this era, Rockville served as a stagecoach stop for those heading west of the Mississippi River. The hilly area, still traversed by gravel roads, now consists primarily of farms and woodland.