Whoa.....no painty the inside, John. The paint flakes off real easy and could harm the bait. (so I've been told) I bought a Blue barrel and painted the outside white. When I looked into the paint, I was told to use this special primer, then follow it up with that sealer then sand it down and do this........turned out to be about $50 worth of paint prep products.....paint still chips off
I'd just go with a few cans of regular spray paint. It doesn't have to be purty. Then as it chips away, maybe spray a little more back on. Just hafta keep the herring cool.
As far as filling up the tank, just use the standard 5gal bucket and 8 or 10 trips to the waters edge. We usually fill at the Wareham run as they have a hose that pumps out the river water. Makes it a bit easier. Then as we need it, we hop down to one of the lots that's close to the canal or beach and fill a few 5 gallon pails up to put into the livewell.