CLE-MSY on AA - routing through DFW definitely gives you more mileage for your buck than the traditional routing through ORD (and was a few dollars cheaper on the random dates I checked). If going directly from MSY to LAS - some really interesting routings through MIA popped up for a few dollars more than the more direct routing. You might also want to try the NYC promo thing to FL as you suggested, nesting your LAS in one of the runs. For example, EWR-MIA-LAS-MIA-EWR was not unreasonable given the mileage involved and possible completion of the promo with another NYC round trip. It's all about how much time you have available. Good luck!