Wow, thanks so much to all three of you for the fast & very helpful replies.

Sounds like starting with either LAN or AA should be fine.

Gardyloo - oooh, great tip about the JFK transfer and doing a Platinum Challenge. I had seen the challenge mentioned in another thread and spent time learning about it, but figured it wouldn't really work for us since our AA flights were at the end. I had NO idea about the fine print which allows a transfer in NA (every time I read the rules I learn something new!). I will definitely try this - if we can get the Platinum status near the beginning it would absolutely be worth the extra time on that route. THANKS!!

Now I've got some more work to do... can't think of any more questions at the moment but surely I'll be back

Yay for travel!