My first river trip was with some friends from Maine, and they brought the cook kit. There were a bunch of pots and pans we carried in a falling-apart, slat-sided apple crate. I can't recall what all was in it but distinctly remember a larger-than-average, cast-iron skillet, and that the pile of pans extended past the top of the crate. We'd tie it off with string before loading it, but in the event of capsize I'm sure most of it would have gone to the bottom.
Smitten with river tripping, I soon assembled my own kit, which I packed in a 5-gallon bucket, with a snap-lid closure. Plates on the bottom, then a 4-piece, non-stick, aluminum cookset from which I removed all the handles so that the pots nested. Next in went my Coleman Peak stove. Utensils got wedged around the edges, and food for a weekend trip fit on top of it all. I was really proud of my little kit and certain that it was a big improvement over the apple crate.
I fell out of using the bucket set up for a number of reasons. Probably foremost was that for health reasons I changed what I ate, which knocked me out of group meals. Not sharing meant I didn't need the plates and the larger pots, which was half what went into the bucket. Somewhere along the line I picked up an Action Packer crate and began carrying food and cookware in that. The AP isn't water tight, but neither was the bucket. Both proved effective at keeping rain, splashes and small vermin at bay. I liked the AP because I could more readily see and access the contents, and I could slide it under a thwart. Also, recall I didn't have a gamma lid, and it was a lot easier to operate the lid on the AP than the snap-lid of the bucket.
A side benefit of the bucket is having a bucket. I used it to settle out grit when processing silty western waters for drinking, to collect clams and muscles at Assateague and to gather pine cones and sticks for kindling. A bucket is a useful thing. I guess I could use the AP crate for those things, though the lack of a handle would make it cluggie. My most recent use of 5-gallon buckets was, paired with a gamma lid and wag bags, as a vessel for human waste disposal. Bless those gamma lids!