You might try what I've done when I've booked award travel to Europe: book the transatlantic leg now, and buy the domestic ticket. Sometimes you can get a very good deal on that portion. Or, simply book the transatlantic portion now, and then hope that some seats open on the domestic leg---you can change your award ticket for a small fee, or decide to buy the domestic ticket closer to departure.

Are there any other cities close to your destination that might work as options?

Good luck!