I started out using a small torpedo on the floor just inside the door. Verified that the fridge is level if the floor is level. Then later I verified that the floor and the frame up front match, so now I just use the torpedo on the frame. I have the stick-on ones that I bought when I first bought my trailer, they're still in the original packaging. One of these days when I have the trailer perfectly level, I'll go out and stick them on someplace... been saying that for a year and a half now...
2014 Jay Flight 28 BHBE
2015 RAM 2500 6.4L HEMI, Tradesman 4x4, 3.73
Blue Ox SwayPro (BXW 1503)
Upgraded from an REI internal frame backpack and a Eureka 1/2 dome tent!