What do you think about how mink run the big two or more section concrete culverts
don't even worry about it. I've just never had much luck setting up such things- and more to the point, they are rare around here. most bridges are rip rapped underneath, and are hard set ups.
I have sets out at exaxtly 3 bridges on my line, and all those are normal blind sets.
As far as following edges- as a steadfast rule, I find it much more true about yotes, than mink. Just like the advice "mink investigatye every hole" is more untrue than true.
Mink follow edges, yes- but only in certain types of areas. If these edges are in hunting areas, and/or danger areas, mink will follow edges that are close to cover.
Smaller creeks. Actually, I avoid all larger rivers/creeks around here- for one simple reason. Those freeze up first and stay frozen. Plus the fact I don't like setting them- no real "edge" and unstable water. But in anycase, its te type of feeder streams. Here, almost 100% of the feeders into the 2 big rivers here- the old Mississippi of course, and the Zumbro, which is a smaller, canoeing type river- are spring fed, trout stream water. Prey is prevalent and in clear water, easy. Plus, you have grasses growing and overflowing the banks- prime spot for what I believe is one of the most important if not the most important prey base for my mink- shrews and mice.