There's no way to see it as the player will in game other than going through the looking glass. I'm not seeing anything allowing for FOV adjustment in the render window either. Keep in mind you can also use the spacebar to pan the camera around just like wheel-click.
actually, you could do so in geck (assuming extremely high ctd-tolerance that is

), no idea what happened to this functionality in ck (in geck, iirc you hit # to get that mode)