is there anything to PHL and train it up or do a 1 way car rental or LGA or JFK and take a Shuttle to EWR.To be more flex look for aday before and Hotel it @ EWR the nght before, as AA has 1 flight a day into EWR non-stop so with connecting and then having to change Terms it doesnt leave you many options at all.
Or ask if the LAX-LHR or DFW-Erope flight are available and connect with LY,IB,BA, AB (Air Berlin) from there