There is no need to get out your carpenter levels. As long as it feels relatively level while you stand inside is close enough. You should have a system in place that allows you to make some adjustments. Most use leveling blocks. Some use the TC jacks. Some use both.
2009 Silverado 3500 dually D/A, Supersprings, Stable Loads, Bilsteins, Hellwig Sway Bar.
2010 Arctic Fox 1140 DB, 220 watts solar, custom 4 in 1 "U" shaped dinette/couch, baseboard and Cat 3 heat, 2nd dinette TV, cabover headboard storage, 67 TC mods