Note: Some people are having trouble getting DevilBro's original mod to work. I'm not sure why this is, but I'm looking into it when I have time as DevilBro doesn't seem to be actively working on their mod anymore. Both the original and my recolor work for me, and hopefully they'll work for you.
To install:
Backup the un-modded files listed below.
Replace farmhouse_tiles.xnb in the Content folder and farmhouse_tiles.xnb, Farmhouse2.xnb, and Farmhouse2_marriage.xnb in the Content/Maps/ folder.
The bathroom after the first house upgrade optional file requires the main file for the second upgrade as farmhouse_tiles.xnb is only in that file.
Thanks to:
DevilBro
adelein13/Serpentwined