I looked at their website and it looks like most versions are available on steam. Are you saying you ran the game on steam and it allows you to use your RC2 controller for input? One thing I've had a difficult time trying to do is to find...
That is assuming you are in an area where you have cell service - if you do, you are fine, but if you don't you are kind of out of luck - I learned the hard way.
It happened to me once a few years ago - I fly where I hike which almost never has cell service so I couldn't login and was pretty much stuck. Its on my checklist now to make sure I do a test flight at home if it has been a while since I flew...