Trailering to a race in freezing temperatures

I’m heading to Vegas for a race in 4 days. Weather forecast show freezing temperatures on our way there and we plan on stopping in Utah for the night where it’s supposed to drop to 25 degrees. The car will be in an enclosed trailer but it isn’t insulated and I’m worried that my coolant will freeze. I’m thinking about draining it before I load the trailer and filling with antifreeze for the trip and do the reverse when we get there, and then doing it again when we make the trip back home but that just seems like a huge pain in the ***, not to mention the mess we will make trying to do that 1200 miles from home, at a racetrack that probably won’t be too happy about us draining antifreeze in the pits.

What are my options? Who has travelled in freezing temps with their race cars before and what did you do to protect your engine/radiator?

Thanks in advance,
Bill