Welcome to FT,
Snoopyo.
A lot of your questions can be answered in the AA forum. The are several Canadian AA flyers (including me

) that hang out over there. Ottawa as a base is not the best for AA, but not impossible. For your mileage run question, a few more details would help. Are you going from CLE to MSY then on to LAS, or are these separate trips?
My email address is in my profile if you need any specific questions answered.