Clouds block the sun on the last Wednesday morning of the season at Knoebels Amusement Park & Resort. But the parking lot fills with cars nonetheless, as families turn out for a final taste of summer. This year has been less kind than most to Knoebels, which straddles three townships and two counties in an area so rural, the park doesn't have a street address. (Its location is commonly given as Elysburg, a Northumberland County village about two hours from the Lehigh Valley.)