Brian, depending on how technologically impaired you feel and how fat the budget is...
That Alfa sells for $35 on Amazon then all you need is a longer USB cord to get it out of the cabin. Yes, the USB cord length limits position but for $35 versus 250+, I'd try it first.
Which also means you'll need to use the Wifi tools that come with your computer, to choose and connect to a network. Which isn't such a big deal these days.
The many folks who repackage it...OK, they're entitled to a profit if they make life easier but really, how badly can you lose by trying the $35 solution first? And at that price, you can carry a spare and sell it to the next hapless cruiser. :-)