Finally did the first coat of fresh paint on the interior ceiling! Simply white eggshell all-in-one zero VOC from Homedepot. Used a large and small roller plus a paintbrush for the creases.
Before I painted, I did a few things to prep the ceiling panels.
First, I sanded the existing vinyl paint that was applied overtop the original paint.
Second, I scrubbed the panels with soap and water to degrease them and remove any sanded residue.
Third, I used standard white caulking to seal the seams of the overhead lines and the area in the rear of the trailer where I had to manipulate the fiberglass panels.
We worked quickly and painted the interior in under and hour, there are still a few places that need another coat but it already looks amazing.