I assume you are referring to Adventure Cycling's Atlantic Coast route.

I live in Philadelphia. You can hit freezing/near freezing temps at night in late October/early November, especially when you head into the farm lands southwest of the city. And the days might be in the 50s at best. Then again, it could also get into the 70s or even higher. I have ridden in summer attire in December more than once. The point is that you will have to be ready for extremes.

Also note that finding legal camping from the Delaware Water Gap to southwest of Philadelphia will be tough. Worthington State Forest at the south end of the Gap stays open until the end of the year, but Bull's Island further south in NJ closes at the end of October.