I sketched out a minimal set of 15 different tiles. I've got nine of them done now, and the hallway/3" tiles (that's another 3 of them) should be easy peasy. I'm debating just leaving the paths the way they are for a 1.5" grid, but I might consider widening the paths to be 3" wide for the 1.5" grid.
I think with this set, I'll make one... no two new walls that feature wooden doors. I have in my mind a wooden door with a rounded top, a square window with iron bars on it, and an iron door handle. Maybe if I'm on a roll when I get that far, I'll consider a double-height wall with a large door on it. Kind of fun to do those for more imposing buildings.
Here are tile tiles so far: