There's a series of documentaries that run periodically on public television -- I think the filmmaker is from Pennsylvania. The films feature roadside attractions, farmers markets, and specialty venues for foods like hot dogs, ice cream, and sandwiches. Anyway, Carls was highly rated on the ice cream episode. Yumm!!
I've seen a special on Public TV and on the Food network. I think its the same special on Ice Cream and all the good places that serve it. They go around the country to many of the Mom and Pop Ice Cream stores. They did have Carls among the ones they visited.