If D and BF will have a car, have them pick you up at the airport. The airport is an easy 10 minute drive from Center City (straight down I-95 with clear signage). There is a free parking lot where they can wait for you to call them to say that you’ve arrived. Once they pick you up and you stow your carry-ons in the trunk, it’s 10 minutes back to Center City and the great suggestions made above.