at present my ground plane looks slanted, esp with the bed above it tilted. how can I make both ground and bed have same flat perspective, i.e. lines of bed and cloth plane parallel with horizon line?

drawn

Have you tried using the Orthographic cameras to line up your props?  Those are the Left-, right-, front-, back-, top-, bottom- cameras.  They do not give you the 3D perspective view like the other cameras, no rotational movement.  By dividing the preview screen into multiple viewing panels, each panel can be set to a different camera.

With the GROUND object selected, open the Parameters palette and set x, y, and ZRotate to zero

Check translations also. Set to zero if they have been moved from the origin.

thanks,, gang, and I almost have it licked, but now the cloth object forms curious lumps right over hie shoulder and arm and has natural looking folds elsewhere. how can I stop this?

Did you rerun the cloth simulation after making the changes?

Yes