It is unlikely that you will be able to get all the miles you need in an AOR if you are limited to OW. If you are willing to use AA miles for one-way, and UA for another one-way, you can probably get enough UA miles for a one-way by applying for a UA card and a CSP. You should apply for the CSP ASAP, as rumor is that the current offer will end Monday and either the bonus will be reduced, or the minimum spend increased.