i find the best way to do this (either route miles>points/vversa) is that if you purchase a 'package' ... you can use the surplus to get incredible transfer rates.

I've done it about 5 times from Marriott to book a resort and then push 50K points to AA miles and did it once from AA to marriott when i had more there.

It was VERY attractive - and the nice feature is that they just 'deposit' the equivalent in the other bucket ... so you don't to even immediately use them.

but it's by far the most beneficial to transfer them. You just basically have to committ to using something. But it sounds like your trip has already commited the miles to a flight - now you're just trying to lock up the rooms. I'd call AA reward services and you might be surprised.

I've LOVED that loophole going the other way from MR to AA.