Thank you for such a generous offer! Although I don't think I'm able to take your offer, if things change, I hope you don't mind if I do.
I just bought my ticket for August 8th, arriving in Philadephia on the 9th at 12:45 am!

I may just stick around for the first train or rent a car, in which case I'd take you up on your offer the next day when I need a ride back from dropping the car off.