Originally Posted by s2mikon
I used a general use CAD program on mine. Cardboard aided design.
Pencil and paper, measuring tape, plastic architect's scale, cardboard templates, pieces of string. Whatever works.
Not as if we're talking so much space anyway... I hope to have that much space with which to concern myself.
I don't have AutoCad personally, and I no longer get paid to use it.
There are several good CAD programs available free and open-source.
And there are several commercial CAD programs for less than $100.
CAD is a powerful tool for planning any space. But for something like layout of a bus floorplan, AutoCad is expensive overkill. There are far cheaper less complicated CAD software available.
There's even free open-source software you can use to model the entire interior in 3D if you're up for it.