Betty is a Valvodian Galactofreight Hauler made to look like 1974 Kenworth W900 semi-truck with cartoon rockets strapped to nacelles on each side of her trailer.
Her interior is laid out like a classic semi cab with cutting edge Valvodian navigation and operational systems. She has four-dimensional haptic touch computer holoscreens inlaid upon faux wood and vinyl dashboard right next to analog dials switches and pulls.
The rest of the ship built on trans-dimensional technology. She has four main decks and a few lower decks including the engine room, but appears to be a normal-sized semi truck on the outside. The cargo bay is where most of the trans-dimensionality exists and has no limit to the amount of cargo it can fit. It theoretically can never be full.