Hey folks, a question that is not screaming at the devs about something

I have a computer at my in-laws home that I use when up there visiting as well as a system at another family members home. Both systems do not have the nice internet speeds I have at home and downloading the game to play when I am there would be a nightmare.
Is there a simple way for me to copy the game I downloaded on my system at home and take it to the remote system on a flash drive or external HD for installation?
True honor need not be named