You can easily fly without a compass, at least if there is some sun shining. You know where the sun is in the sky (E in the morning, S at noon, etc) and your struts cast nice 'sundial' shadows on your wings. Quite simple to know what direction you are travelling.

And of course with Lou's maps you can navigate even on a cloudy day by hoping from landmark to landmark.

Neither is there any need for an altimeter. With practice you can just look at the ground and you will know (roughly) how high you are. (for practice, take a guess then check answer with the z-key, adjust brain as necessary).

Yeah, the only negative to that (and there may be a setting for this), is that with Trac, the gauges move with my vision rather then stay affixed to the plane. Not an issue for me really. Didn't even realize it until this thread.

On the planes with full gauges (or at least the important ones), I use them, but both ways still feels real enough for me. Realism is in the mind mostly. I don't have to sit in a walk in refrigerator with an industrial fan blowing on me to immerse either. :P