I'll bring up something to consider.
How long are you planning on keeping the camper?
Do they use salt on the roads in your area in winter?
Is the camper stored outside uncovered most or all of the time?
I restore older campers, mainly the 10 to 20-year-olds range. All of them were not stored inside or had minimal cover when outside. You can learn a lot from an older camper on how things fail.
Frame ground is bad news as a wire conductor as the camper ages when exposed to the elements. The DOT lights use frame ground, the brakes are often set up from the factory using frame ground, the LP pipe, and, yes, battery negative needs to go to frame ground. Corrosion is alive and well in an older camper when stored outside. Aluminum or copper connectors on the wire to the frame are also exposed. This frame ground setup works as a DC conductor when the camper is new. As the camper ages, the corrosion will start making issues.
During a camper restore, I added a DC negative wire to the brakes and the DOT lights to eliminate the frame ground, as the wire connection terminals and the rusted metal connections were all bad. The camper brands I have worked on had the power converter already set up with DC negative with a wire directly to the converter. The weak link, though, was the exposed aluminum terminal block which joined all the DC ground wires at the frame by the battery. That area also gets corrected.
The suggestion is to run your upgraded heavy wire on the DC negative to the power converter if you want to keep the camper for a long time where corrosion conditions exist, as I asked about above.
Hope this helps
John
2005 Ford F350 Super Duty, 4x4; 6.8L V10 with 4.10 RA, 21,000 GCWR, 11,000 GVWR, upgraded 2 1/2" Towbeast Receiver. Hitched with a 1,700# Reese HP WD, HP Dual Cam to a 2004 Sunline Solaris T310R travel trailer.
