Looking at a series of designs for a pseudo-medieval (D&D style) overland wagon train, incorporating a number of elements, such as a specialised “grand” private wagon, a mobile strong-room and/or guard wagon, a huge mobile “court” or formal audience chamber, a and a regular multi-purpose wagon.
Some of the designs incorporate a set of tri-form wheels/axles, for movement through rough terrain, with a series of “chucks/chocks” that can be added to each set to create a regular wheel.
These were just sketched out in an fairly intuitive bit of iPad based 3D software, but would be just as viable in sketch up or similar, as these aren’t for for further development in 3D but more likely paint-overs in Procreate.