Let's talk about moccasins. Reverend Doddridge, writing in the Eastern hills in the late 18th century, Reverend Doddridge described wearing moccasins as a "decent way of going barefoot."
After spending many days in the woods, fields and streams in moccasins, I agree wholeheartedly. Moccasins were generally made entirely from soft deer, moose or bison skin.
Old lodge (tipi) tops were often used, the heavily smoked hide making great moccasins. Hard soled moccasins did not come about until late in the 19th century.

From W.A. Ferris:
The thorns of the prickly pear are
sharp as needles, and penetrate our feet through the best of mocassins; they are extremely painful
and often difficult to extract.

From George Catlin:
A white man, to reach this village, must travel by steam-boat -- by canoes --
on horseback and on foot; swim rivers -- wade quagmires -- fight mosquitoes -- patch his moccasins,
and patch them again and again, and his breeches; live on meat alone

From W.A. Ferris:
In the evening we dried our moccasins,
ate some dried meat, and finally threw ourselves down to sleep, covered by our two blankets;
and as the night was pleasant we rested well, warm and comfortable.

From General Thomas James:
Our moccasins being worn out, fell off and our feet were perfectly cut up by the prickly pear, which abounds on
these prairies.
We had caught a few beaver skins in our
route from the Gros-Ventre village, and were employed ourselves in making moccasins and
leggins and in killing game which was very plenty all around us.

From Charles Larpenteur:
about eleven o’clock at night I entered Fort Union with my feet nearly frozen.
As this was the end of March, and it had thawed all day, the river bottom was all water; but at
sundown the wind changed to the northwest, the water commenced to freeze, and when I got to
the fort my moccasins were so hard frozen that I had to let them thaw before I could get them off.
Had there been an hour longer to travel, my feet would surely have been frozen.

Typical vamp style moccasins as seen in many of Miller's paintings, from the Rocky Mountain Outfit of the American Mountain Men.

And after wading icy mountain streams with them all day you couldn't take them off at night to dry or they would shrink so much you'd never get them on again right K?

I've read that once or twice is all. My thought about that is that they were wearing field expedient moc's made from poorly tanned, or untanned, hide.
I always put on dry moc's before crawling into my bedroll and prop the wet ones by the fire to dry. In the morning, dry moc's get rolled up in the bedroll and wet moc's go back on for the day.

You're probably right K.

Hear mentioned in several texts taking multiple pairs of mocs on expeditions. They were a standard item of trade and ubiquitous out past the frontiers. One thing you don’t hear mentioned much is just how slippery they can be.

Absolutely. In rough country you can wear holes in a set of moc's in a day or so. In the woods you can get a coupe three days out of them. There are a lot of entries detailing making new moc's or repairing moc's in the field. And they often carried a few dressed hides, presumably for making more moc's.

And slippery? It's like wearing ice skates any time you are on wet grass, loose leaves, sand, snow, ice, pretty much all the time. You learn to walk different in them.