How do you level a motorhome front to back?

I didn't level the coach perfectly. I stuck the levels on even with the door and dash trim. When I use them to help level, I use a bubble level in the refrigerator to make the final judgement. Half a bubble out of level is acceptable. I can't really tell the difference inside between that and completely level bubble in the middle. The graduated levels probably are not all that accurate anyway. We keep as level as we can to extend the life of our refrigerator and to make the water drain well.
Was there something wrong with my cab trim logic? I may have overlooked something about leveling. I am obviously not a perfectionist. :)