Not sure what you are intending to do by way of prepping for winter camping but I can almost assure you that could be freezing in Dallas area based on its elevation and latitude, relative to where I did winter camping - Eisenhower State Park in Texas, 1 hour north.
Woke up a couple of mornings last winter at just about freezing, and one night the water was almost frozen solid in the hose. The next night I disconnected the hose and saw an icicle on the hose hanging over the spigot.
Last weekend I bought a 25' heated PIRIT hose
which is on sale presently. I will devise a wrap for the spigot-to-hose area. The water pump area has a small heater that I can use - some people use a bulb. I have heated tanks and an enclosed underbelly.
If your dump valves are outside of the enclosed underbelly you could wrap it with a thick layer of padding to stop the wind chill.
What is the name of this Dallas Park you found?