Wanted: 3D Environments for Idiots!

I am NOT a programmer or a CAD/CAM designer. For a lecture I am working on I want to create several unusual looking rooms that might be found in a castle, complete with unique furnishings, export the rooms for use in PPT, and then, in PPT, add different things to them. As an alternative I could export to Prezi.

Does anyone know of software that is specialized for easily creating 3D furnished "rooms." The standard interior design software seems to favor typical suburban homes over fantasy castle interiors.

Any suggestions gratefully received.

Thanks!