That it's slowly been populated by big-city folk in search of small-town charm hasn't harmed McKinney they came not to speed up the city but to slow themselves down. In fact, it still looks like it did when Joe Camp shot his first Benji up there-giant old homes with rustic front porches, a town square anchored by an old courthouse. Now it takes 20 minutes, without much traffic, to head up to this Collin County town that's growing every day without losing much of its charm. When we were a kid, last month, used to be a drive up Central Expressway to McKinney lasted a week 75 was one lane north and south, and it wasn't so long ago.