If you use Triiforce then you can make life easier.
Triiforce will let you install them to SD/USB and run from there, plus the saves will be saved to the SD/USB too. Now to play on another Wii just plug in the SD/USB
The Wiis must both have a waninkoko cIOS rev 14 or higher installed.
imho Triiforce is what you need here.
It will save room on the real nands of both Wiis by not installing the games or saves to the real nand.
@ wyndcrosser, no you can't just use the Wii interface to copy to SD and play on another Wii, if you could Nintendo would be dumber than a dumb person (think about it). They are signed to 1 console only.