Is a trip to Sesame Place worth flying my 4 year old and me from Nashville, TN to Philly, renting a car, and driving to Lancaster?

Sesame Place is fun, but you'll be disappointed if you come all the way from Tennessee. My advice would be to go to Hershey Park instead, which is located near Harrisburg (about 100 miles west of Philly.) Hershey Park features a chocolate factory in addition to rides. People come from all over to visit this park and usually stay a few days.

Sesame Place is not near Lancaster. Hershey park is ok for a 4 yr old but your child would probably enjoy Dutch Wonderland much more suited to the age. But to fly up here just for that is NOT worth it, unless you have money to burn.