I can recommend softmodding instead of a modchip.
My old chip is still in the wii but pretty much useless.
I know you already made up your mind what you want to do etc. but it sounds like running backups and this can be done
for free (best plus on the softmodding)
no need to open up your console (already done that? a triwingscrewdriver around?)
have the whole game collection on a usb harddrive (if available)
you can still use discs of course
and with even more options to go for.
run DVDs, .mp3s, .avi, radio live streams, youtube, virtualconsole stuff/emulators etc., sooner or later you/your girl maybe want something of that
Have a look at the softmod any wii guide (link below) and stick to the route which suits your wii systemmenuversion (-->wiisettings->top right corner)
takes about 100Minutes to read but only 20 to get it running.
--> Fully enabled wii
good luck, what ever modding route you take
edit: later updates will make things harder for you either hard or softmodding, but with softmodding you will be able to block any update action (most chips should have that too). using the shop or other online content/activities is not firmwareversion dependend