Maybe you should think about alternative approaches?
The usual approach is to have a nice, readable map which shows the whole level. Ragnarok had this map take half of the screen, and a 7x7 region with large tiles.
You can also go the route used by Zaga-33 and MicRogue: simply have small levels, so everything fits, even with large tiles.
My HyperRogue solves the problem in a unique way, but I suppose you do not want to try this.