Thank you very much for the responses. I am going to draw now for a little bit.

The techniques for making dungeon objects look fantastic, and I think I will start off by making some objects and then start on a dungeon when I get a good concept for one.

By using layers, it should be easy to make two versions of any dungeon map- one that is bare of furnishings (except for stairs, doors and immovable objects) for VTT players, and one that is fully furnished and reveals any secret aspects of the dungeon, for game masters.