I agree with the others posting about using a 2-foot level inside. I have an aluminum one we use inside on the floor. It stows easily, weighs nothing, and is big enough to give you a decent read. I bought stick ons, then never used them (they seem unnecessary).
Welcome to the forum.
2013 Windjammer 3008W
2006 Chevy Silverado 2500HD 6.0L w/Equalizer 4
Nights camped: 2012 (29); 2013 (26); 2014 (40); 2015 (43); 2016 (35)