What kind of windows, siding, etc?

In general there shouldn't be any trim under the exterior window sill. Trim in that location can often interfere with the drip function of the sill and can cause leaks to the interior or behind the siding. For a modern nail-fin window it is sometimes a good idea to add a projecting PVC sill nosing that extends under and to the outer edges of the jamb trim and overhangs the siding forming a proper drip. That detail has been working well for a half century so it's best to go with what works.

The exterior trim is often thicker than the interior trim since exterior siding usually butts against it and it is not mitered at the top corners. Sometimes it has a band molding along its outside edges but usually not for a Craftsman Style.

Interior trim usually has a more complex profile but Craftsman trim is usually made up of multiple simple profile pieces to create a more complex, artistic appearance. For a traditional window the interior bottom trim should be a projecting "stool" that projects under the jamb trim with a thinner tapered apron trim below it.

Not all internet sites deal with true Craftsman detailing. It is best to think of "artist" and "woodworker" crafting rather than of "carpenter" and "builder" crafting. It was a back to handcrafts and natural materials movement but on a high aesthetic and skill level contrary to the way builders use the term today as a euphemism for simple cheap detailing.

A search for "Craftsman trim" will give you many examples but weed through it carefully.

Here is a link that might be useful: craftsman trim search

Here is another site. Searching for Greene & Greene also helps.

Here is a link that might be useful: Craftsman trim provider