I know you said you're not fond of Delta, but it's probably the least hassle, via either ATL or JFK. You can also credit the miles to CO. Second best would probably be DL to JFK, then Aeroflot to Moscow. Aeroflot is also Skyteam, so you can still get the miles credited to CO.

Other than that, you're looking at double connections or airport changes (LGW-LHR).