I just got done shipping 2 of them in one 'box'. The 'box' I used was actually 2 very large 4 ft long boxes that I had stored in my attic, left over from other goodies. (I always save big boxes) It was somewhere near 48 X 24 X 16 or so when I morphed the 2 into one.
If your attic is not quite as well supplied as mine, you might get lucky at an Appliance retailer. (Stove/refrigerator) It will require some 'U-fab-it' knife and packing tape action,,, Lotsa packing tape. And 'stuffin',,,, (I keep the 'stuffin' as well, as long as it ain't them dayum 'peanuts'!).
When I run outta stuffin' I raid the wifes stack o' newspapers she saves for coupons....