Our coach came equipped with an auto level system (Dewald). Our previous coach (Hurricane) did not, and we had a system installed. Neither one worked very well when it came to getting it accurately level. I just use the manual setting in combination with a dual direction bubble level that I got at Home Depot (about $3.00).
Another trick, for me, is using either the bathroom door or medicine cabinet door as a guide. Open them, and if they stay put you're fairly level. If they swing either way on their own, you need to adjust.
'03 41' Friendship & 24' trailer with HIS '03 H-D Heritage Springer, HER '15 H-D Freewheeler Trike, and '08 Smart Car.
"Adventure is found in the journey, not the destination."