I built this simple itinerary on Orbitz. Decent price of under $1000 return
Only 1 connection on the way back and that's on the way back. I recommend if you're going to BCN to stop by Palma Mallorca for the day.
Fri, Oct 1 Depart: 6:25 pm Philadelphia, PA (PHL) US Airways 742
Arrive: 8:35 am next day Barcelona, Spain (BCN)
Mon, Oct 4 Depart: 9:35 am Barcelona, Spain (BCN) Spanair 5704
Arrive: 10:25 am Palma Mallorca, Spain (PMI)
Wed, Oct 6 Depart: 9:00 pm Palma Mallorca, Spain (PMI) Air Berlin 9475
Arrive: 11:55 pm Copenhagen, Denmark (CPH)
Sun, Oct 10 Depart: 8:35 am Copenhagen, Denmark (CPH) SAS Scandinavian Airlines 539
1 stop
Arrive: 2:00 pm Philadelphia, PA (PHL) US Airways 735