directing Filming in a Cold Outdoor Location

So I am prepping for an outdoor shoot this weekend.
I am thinking ahead, and getting some things.

I am going to buy a lot of the insert-able pocket/hand warmers. Bringing some blankets and I will already have some propane tanks.

My question is, with a low budget production, should I buy a tarp tent or pop-up gazebo (this is EXPENSIVE), to have a heat able staging area?
my goal is to have this area be the hangout spot for people who aren't busy.

I will already have propane tanks (slim torch kind) for the portable liquid fog machine, so I was thinking about buying some portable propane heaters for the tent as well.

Most of the cast/crew are from the location, so they are used to this weather, but I still want to be prepared for everything.

The day is planned to be short, at around 4 hours tops.

Anything you think I am missing with my plan? Are there cheap options besides what I listed to keep people warm in winter conditions?
pretty sure you can buy a large tent for cheap

what i would take into consideration is the wind chill. how windy does it get? do they need shelter from the wind

If it will be too windy, then we may not be able to film. Its supposed to represent the cold dead surface of the earth sans sun.

That said, the only shelter we really have would be our own vehicles.