First paint the 1/32" basswood parts while they are still in the carrier sheet. Use several light coats of paint to minimize warping. If you saturate the parts with paint and do not wait for them to dry thoroughly, the delicate parts are easy to break. I used PollyScale SP Letering Grey for the walls.
If warping makes you nervous, brace the parts first and then paint them. Adding the bracing makes putting the windows in a little harder which is why I wait to brace after the windows and doors are in place.
Here you can see that the parts have warped a little. Do not worry about this at all. Bracing will take care of this problem.
Again using light coats, paint the windows, doors, undersides of roofs, and covered stairwell walls. I used Polyscale Dirt for the trim.
Flip the carrier sheet and painted the backs of the windows and door trim. This helps get paint on the inside edges that will show once the parts are in place.
Retouch parts that need retouching. Light coats.