Just on the US immigration aspect.

1. do not lie to the customs inspector. They take training in looking for liars, and if you do, the red-flags every time you enter the US for the next 5 years isn't worth it

2. So that means being honest... Take printouts of what it takes to be AC Elite, what your current mileage is, and explain what you're doing. I did a YYC-SFO-IAD-MIA (7 hours) MIA-SFO-YYC, which is a pretty sketchy one (so you're going to Miami not to get drugs...), but explaining it, the customs agent was rude, but laughed at the end of it when I explained about the 'perks' for my upcoming employment (all true).

Caveat empetor...