The most important thing to have level is the fridge. Use a torpedo level that will fit in the freezer or fridge making sure where you put the level is flat and free of anything like ice that will throw things off. Level the fridge front to back and side to side, after the fridge is level apply your outside levels to the front corner of the trailer where they can be seen easily.
Before unhooking your rig check the side to side level to see if you will need to raise the tires on one side to get the trailer close to level. After unhooking your TV level the trailer front to back then finish the side to side level with the stabilizer jacks. A half of bubble off level really isn't all that much and I find it acceptable in my trailer.