Yep Toddy is spot on, that is what I do when travelling.
I have the 64g iPad 2 and it holds quite a lot of footage, mind you I am usually just recording surf and usually in Bali or somewhere where I often have trouble with fogging, so often just turn it on before catching a wave and off whilst paddling back out, I haven't shot any long DWing videos.
When home I usually hold the camera and open case in front of my car air conditioner for a while before closing it as air from an AC is dryer and it helps with fogging issues but often in Indo I haven't got that luxury and with the humid conditions it fogs up pretty quick if left recording video.
Just pull the SD card out every day plug it into the adapter transfer the footage to the iPad then delete it from the card so you are good to go again with an empty card.
Just make sure you don't have a skin full of beer and accidentally delete the footage before you transfer it (hey Radman), that's what I did on the very best day of a kiting/SUPing trip and lost some awesome footage.