I don't think I would worry about it. If I remember right, pex pipe can take 10 degrees F for 24 hours without damage, with water in it. Noe for your traps, if it is very cold, when you stop for lunch, go in and turn on the furnace to 50 or so. Shut it off after lunch and good to go. AS for the tank heaters, good to have them at night, but I wouldn't run them while traveling. Moving liquid seldom freezes until it is very cold. The pump will take a while to freeze, and if you heat the trailer mid day, it will be fine.
Now all this is opinion. I have nor real experience doing this. Think about this, you put water in ice trays, and put the trays in a 20 degree or less freezer. It takes at least 4 hours for them to freeze. If you have spent the night, and all is well, with sun shining on your camper going down the road, I don't think you will have any problems.
Good luck and hope you have a safe journey.
2012 Ford F250 ext. Cab 4x4
2002 Jeep Wrangler Sahara
2008 Yamaha V-Star 650 Classic
2008 Work and Play 18LT