Opps.. just realized that this option may or may not work seamlessly depending on how much you redo your blur (if at all) since you have several torches that are right inside of corners and the blurring might bleed into a perpendicular hallway. Of course, you could always erase by hand and then use the blur tool to fix up those bits if you feel like.
My Finished Maps
Works in Progress(or abandoned tests)
My Tutorials:
Explanation of Layer Masks in GIMP
How to create ISO Mountains in GIMP/PS using the Smudge tool
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Unless otherwise stated by me in the post, all work is licensed under a Creative Commons Attribution-Noncommercial 3.0 United States License.