Thanks so much for all of your responses. I'll try to summarize:

efamous - Yes the AA/BA combination is on there but the LGW connection is too tight. On the return, it would require an overnight in London.

nytango - The connection is required at least for the outgoing as the JFK-FCO direct operates only Tu/Fr/Su. Thru London, the only connection is via LGW, which requires DFW or RDU routing. You're right, though that I could return Mar 14 on the FCO-JFK direct, but it's pricing out much higher at the moment. I had missed it because I'd unchecked Airport Changes on ITA to eliminate all the itineraries with changes in LON. I'll look more into your BRU routing.

MiamiBeach - Thanks for the info on Delta, I'm addicted to AA, though (Also have to fly US/*A part-time, but I have very little on SkyTeam). PresRDC - I have to fly a US flag carrier for the transatlantic leg under current institution policies vis-a-vis Fly America Act for govt-funded travel. I know it's changing Mar 2 for Open Skies, but we haven't yet.

bdemaria and altaskier - Thanks for the advice on the train - I'll definitely check into it!!