We have most of it all packed in one very large suitcase. Just a thing or two left that will be put in one of our carry ons. I didn't put together everything in the bags yet, which makes it a lot easier to fit things in the suitcase. If the stuff is in the OOT bags, then it has kind of an odd shape and will be much harder to pack.
We pre-put some of it together, but we have all the big bags flat and many of the things that go inside are in separate boxes/zip lock bags. It took a while, but we got it worked out pretty good.
One thing to keep in mind is to not have too much money worth of stuff in a single bag either. Each person coming into the country can only have $300 or less in non personal items before getting taxed on it.
I worked hard after finding this out to dig out and print receipts.... still missing some, like for all the crap we got from the dollar store, but I've got receipts ready for the bigger items