Let's take a look at the sleeping arrangements of the Western trappers and traders.
Oftentimes they slept under the stars, regardless of the weather. Buffalo robes and blankets were the typical bedding.

From Rufus Sage:
The bed of a mountaineer is an article neither complex in its nature nor difficult in its adjustment.
A single buffalo robe folded double and spread upon the ground, with a rock, or knoll, or some
like substitute for a pillow, furnishes the sole base-work upon which the sleeper reclines, and, enveloped
in an additional blanket or robe, contentedly enjoys his rest. Wishing to initiate myself to
the new mode of life before me, I was not slow to imitate the example of the promiscuous throng,
and the lapse of a few moments found me in a fair way to pass quite pleasantly my first night’s
repose in the open air.

From Henry Spalding:
and commenced our camps — since
which time the ground has been our table, our chairs, and, with a few blankets, our bed.

From F.A. Wislizenus, M.D. (a rare reference to tents being used):
At night stakes
(pickets) are driven into the earth at some distance from each other, and the animals are fastened
to them by ropes. After we had attended to our animals, and had eaten our supper, we sprawled
around a fire, and whiled away the evening with chatting and smoking; then wrapped ourselves
in our woolen blankets,-the only bed one takes with one-and slept for the first time under our
little tents, of which we had seven.

From John Ball:
I stood this change of life and living about as well as the mountaineers, and better than most of
the new ones at it, and as to a camp life I rather enjoyed its ways. I had for bed purposes, the half
of a buffalo robe, an old camlet cloak with a large cape, and a blanket. I spread the robe on the
ground, wrapped the blanket about my feet and the cloak around me, throwing the cape loosely
over my head to break off the moonshine, and a saddle for my pillow. And oh! I always slept most
profoundly. We had tents, but it never raining and but little dew, we did not use them.

From W.A. Ferris:
“At the close of the day” we retired to rest, in the open prairie, as usual, with a blanket for a bed, a
saddle for a pillow, a robe for a covering, and the clear blue star‑studded sky for a canopy.

Camp fire at night, by A.J. Miller

ifin i went to sleep on the ground a team of big horses couldn't get me up the next morning

I have slept on the ground a few times hunting not over night just a nap , been walking all day , just find a nice divet in the ground full of leaves and lay down gun laying across my lap

generally wake up as it is almost dark and I am freezing.

I would think a well oiled buffalo hide under and over would keep the damp of the ground and the cold that settles in away decent.

mine is usually in November and I am wearing snow snow pants and coat.

Getting insulation under you is key, I think. If I have two blankets, I'll put three layers under me and one over me. I've also used deer and bear skins under me, those work very nice.

And a good hole for your hip to fit into goes a long way to being comfortable.

As a kid I used to take "siestas" wherever I felt like it. One time a neighbor was walking across his hayfield and happened upon me asleep in 3 foot tall hay. I guess that startled him pretty bad.

When we read period accounts we tend to think in modern terms but that often isn't correct. I wonder what their "tents" consisted of. Military tents of the period were typically wedge tents not much different from what we use at rendezvous events. Wedge tents would be quite a load for a trapping brigade to carry. I wonder if their "tents" were perhaps just a piece of canvas that would shed the rain.

Good thing he didn't decide to mow hay that day😇

Been my experience also. That cold ground just sucks the heat out of you. I suspect these guys all suffered from rheumatism later in life.

Lay on the ground here and the ticks will carry you away...

I remember reading about one of the mountaineers (maybe Joe Meek?) that went back east and couldn’t get comfortable in a bed so slept on the floor next to it.

I've done that at some hotels in Europe when travelling for work. The bed is so dang soft my back hurt. So I slept on the floor. I am sure housekeeping wondered what the heck was going on.

Especially when you shook out your buffalo robe when you got up! Lol