IMO once the league gets one, perhaps two teams into the LA area, they'll start looking to expand internationally. We of all people should not wish to have a franchise in Portland because it hurts Seattle as it cuts into our market. The league would be creating two small markets out of one mid sized one.
Same goes for Orlando. Florida already has an over saturated market with 3 teams in the state. CFB and NASCAR compete with the NFL like no other area of the country. The new stadium in Orlando doesn't hardly look to be to NFL standards as the price tag, less than $250M when the costs of new NFL stadiums, even ones without roofs, are approaching $1B. Heck, our place, which is 12 years old, cost over $400M.
They won't put a team into Mexico City simply because it's a poor country with was has been a virtual civil war going on with drug gangs running rampant. Toronto would be an option, except that the league has maintained a hands off Canada approach in order to preserve the viability of the CFL.
Once they achieve their goal of returning the NFL to the country's 2nd largest market, the league will turn their eyes to across the pond.