Here is an overview of the completed pieces along with the ones I did previously:
You can see how the riser lifts the one building a bit higher than its neighbor.
As far as construction goes, I am making them starting with a shell made from foamcore; with balsa wood added for the timbers and wood panels and doors; leaded glass windows made from cross-stitching plastic grating cut at a 45 degree angle; roofs made from chipboard/cardboard with cereal box cardboard shingles and various bits of wood and cardboard for the chimneys and chimney pots. The plastering between the timbers is foam putty/hobbilite filler (basically the same lightweight filler/putty from different manufacturers - it's made for working with foam and sets up lightweight but sturdy enough).
Next on the building plan, I hope to add some stonework pieces.