HI.
It seems like the right forum.

It sounds like you know what you are doing.
I don't know what to suggest except maybe a few extra blankets. Thinking......

Maybe a help flag to run up an antenna?

We use flags something like these ones to increase visibility for our vehicles.
http://www.smsafety.com.au/flag_poles.htm
We use larger pennants, a lot of fluorescent orange for daytime, and a lot of reflective striping so they show up at night.
We try for a 12 foot height on pickup trucks and about 6 feet high on skidoos.
The skidoos because they get operated on roads with regular size vehicles and are too short to be seen among them.
A flag at 6 feet is in the eye line of most drivers and shows over most cars.
The trucks need 12 feet because they are getting operated in mining areas with heavy haulers operating.
Heavy haulers are dump trucks that carry between 350 and 500 tons of tarsand. They can run small trucks over and not even notice the bump in the road.

Since if you get stuck you might not want to try setting out road flares a couple of shorter flag whips might help you get noticed.
We just tie ours down to the racks on our trucks when we are not in mining areas.