I went through this last year for our trip this year (just returned on Wednesday). My advice is while you can now book tix like this on the aa.com, is just use the web for research and don't assume that what you see is all that is available. Even at the 325 (ish) day mark, I couldn't get the non-stop ORD-FCO or back on the desired dates or anything around it, even though I was not requesting weekends.

Talk to a person on the phone and they can get creative in their routing. Although Oct should be easier than Sep.

Now why did I say 325(ish) day mark? because the magic of round trips mean that you can either book the outbound at the magical day mark, and then call back the appropriate number of days later to book your return and hope everything works out. OR not book anything until the magical day mark of the desired return and hope your outbound flights work out. I ended up having to do the latter since we had a set number of vacation days with no flexibility. So we ended up ORD-LHR-FCO, and then FCO-JFK-ORD. It wasn't really as bad as I thought and having the layover in LHR forced us to not land in FCO until 4 PM, so we went to bed around 9 PM or so and voila! our body clocks were now on the right time zone.

Enjoy your trip and welcome to FlyerTalk!