would there be any advantage to enlarging everything except the camera to make the scene more spacious?  That would have to include the "people" being enlarged.

Playing around with the camera perspective can help, but watch out for distortion. You can right click the dial and restore the camera back to normal.

Both these pictures have the camera in the same position. The bottom picture shows what happens when the perspective dial is moved to the left - a more spacious view that seems to enlarge the room. Taken too far it will un-naturally distort the scene.

well I thought if the camera stayed small and the rest of the scene was massive it would be easy to maneuvre inside it.  It was just a silly thought really.

do you mean focal length or is perspective different?

Just the camera perspective dial. You actually have a fair bit of leeway before distortion becomes a serious issue. Try it in a room, back yourself onto a wall and move the perspective dial - the room should appear to grow allowing a wider perspective to view what's in there.

hmm I never tried that before.