According to the "Bust Accord" (a signed contract between Mom and Candice), Candace is not allowed to bust her brothers: (1) during the school year in the time allotted for her to do her homework, (2) at the dinner table, (3) while operating a vehicle or any other heavy machinery, (4) while holding or otherwise in possession of a wild or domesticated animal, (5) while in the middle of an unrelated sentence, (6) from a distance of more than 1900 miles, (7) on the subway, (8) while covered in hair and honey, (9) while pie is being served, (10) while Mom is at the beauty salon, (11) during a date with Jeremy, or (12) more than once a day.
The play the Dr.Doof is in is called the Pizza Man Cometh, spoofing the 1939 Eugene O'Neill play The Iceman Cometh.
Road to Danville is the first episode to have only one plot about Perry and Dr. Doofenshmirtz while Phineas and Ferb only appear in a few scenes.
Doofenshmirtz attempts to attract the world's biggest ball of twine. Weird Al Yankovic has a song called The Biggest Ball of Twine in Minnesota. After Phineas and Ferb, Povenmire and Marsh created Milo Murphy's Law, starring Weird Al Yankovic.
Road to Danville: Fifth episode to have just one plot.