I actually really like the look of that paneling you are using-- I think I might have to use that in my bus! What exactly is it and where did ya get it, if you dont mind me askin?
About the level... I'm not sure if you've considered this, and I only mention it because I had a friend of mine do the same thing in his bus, but unless you know it's parked on a perfectly level drive, a level is not going to be much help for making things 'level' inside your bus. That 1/2" difference could be a dip in your driveway. Jus throwing that out there!
Keep truckin man, you're making good progress