As far as tanks go I have a few options, I have an electric ice chest/cooler that quite working, so I took all the electric out of it, and sealed the hole on the end both inside and outside with a small piece of plexiglass and marine silicone= insulated box. I also have a 55 gallon barrel I can use, cut down a bit should hold 30-40 gallons, uninsulated but rolled R-10 insulation wrapped around outside of tank should keep it from freezing in my shed. I also have a 10 gallon Igloo drink cooler that I found along the road, main body here then lid about 1/8 of a mile farther down. No leaks, lid fits= free insulted bait tank. Options are out there, one just needs to keep your eyes open. Also remember minnows survive in the cold lake water we would catch hyperthermia in. I believe if you keep the water moving, not real fast mind you, well oxygenated, clean, and not frozen, your minnows will survive.
Now summer time is another matter. But fall and winter as well as early spring is when I have to travel great distances, usually in another direction from where I want to fish to get bait. Now when I go get some bait, yes I will spend a small amount of time at the big lake trying to get a bite, just because I went to that area to get my bait to bring home. By bait I'm referring to minnows. I'm told a local store used to sell minnows but they have closed. Next closest place I am aware of is the local marina, ( closed after Halloween, owned by city, lake used for city water supply. Not open again until April sometime). And they only sell by the dzn. Then there's the bait shop I was referring to that sells by the dzn, but it's more like 1 1/2 dzn, but their 38 miles away, real good prices to, by the way. There is a place all the way over north of Joplin some 70 miles away that will semi deliver,( by that I mean they will meet me here in town IF they are delivering to this area), other wise it's a 140 mile round trip, but they sell by the pound= big smile...Eric