[Stiglr]

That's not a dumb question by any means.

In order to do realistic doors and windows, I suppose it would be best to outline basic rectangular areas with either Knife or Divide Surface operations on the walls. Then Combine surfaces so that you have a single door or window surface that's separate from the wall, and move the vertices to make sure the separated aperture surfaces are the dimensions you want.

After you have doors and windows "blocked out", then you can go as wild as you want in making them as plain or as ornate as you need.

To create a jamb or frame, Indent the aperture surface. For ornate doorframes and windows, perhaps do a few layers of indents and bevels, and extrude these in or out to create the desired ornate effect. Finally, select the innermost area and either Delete it to cut out the aperture... or perhaps subdivide it further to create panes, or quadrants for a molded wooden door...etc. Or for a sliding window or storm window, you might only Cut Away Object and use this as the basis for a more fleshed out 3D window object.

For those circular windows in the door, you might want to create a circular Disk object as a tracing guide, align it in a Ortho view, then Create enough new Vertices on a subdivided surface and move them in place to describe the curved surface, which can be deleted or populated with panes of glass (change the Surface Material). (the other option would be to create a cylinder and Boolean Cut it out of the door, but I predict this will create a huge mess of superfluous vertices you'll then have to clean up...but you might try it and see if it works...)

For the eaves above the roof windows, you could create several plys of the roof, and extrude out certain sections and reshape those to create ornate wood facings. Or, if you're working from a blueprint, just trace the shape of the ornate roofing eave, extract the surface out to make it 3D and just Merge it with the rest of the roof.

You have a lot of options and flexibility to do whatever you want. You only have to have a grasp of what is possible, and the ability to "think like the program" to make it as quick, accurate and automatic as possible.

Whether your house is a contiguous object is probably not a consideration. By the time you end up finishing it, at the very least the walls will be separate from the roof, the windows and the doors. But you will create these fixtures from the basic wall structure... if that makes any sense.