Leave yor tailgate at home.
On the pictures of the 1240 I have seen, it has little side skirts wrapping around the truck's taillights.
If your camper doesn't have these and you are able to close the tailgate (which I personally doubt), you can still put it back on and see how you like it.
A rubber / stable mat under the camper is not a bad idea. I am sure more people will chime in.
2014 Ford F350 XLT 6.2 SCLB + 2017 Northstar Arrow