I had a 2wd Ranger and Toyota pickup. Both had studded snows and about 50kg of weight in the back. If it was snowing a lot, I'd let the snow accumulate for a bit more weight in the back. I also had a set of chains, just in case.
I had a Jeep YJ too. If I left the soft top on late into the season, it was a bit draughty, but the heater was strong enough to melt your boots to the floor. You really had to watch stability though, it didn't take much for it to swap ends without warning.
Original Mini was essentially useless through winter. Either the moisture wouldn't let it start, or it became stuck in anything deeper than hoarfrost.