I was thinking today that I should design an outdoor kitchen to build and use next year during the project. And then I thought: how ridiculous, to build an outdoor kitchen for just a couple seasons of use (my parents enjoy the outdoors very much, but I see them more as indoor-kitchen folk). This led me to consider what my parents do want/need. And I think a greenhouse fits the bill, especially if they are going to be living here initially in the winters.
Below is a rough model of the greenhouse. It's about 8X10, interior floor space. The main four panels of glazing will be glass. The rest of the translucent openings will be plastic sheeting (both because it can be cut into different shapes easily, and because it doesn't need to be framed in with wood, so it can extend past the framing to keep water at bay without caulk, flashing, and other fancy drip details). The North wall will be an 8 inch wall of cob inside a 5 inch layer of slip-straw insulation infill (straw dipped in clay slip). The cob will act as a thermal mass to store the sun's heat, and the straw will keep this heat inside. The roof will be shingled (to save money over metal) - I would consider a green roof, except that it would require a much beefier frame to hold the extra weight, and I want to stay as light on materials as I can. The floor will be gravel, raised about 3 or 4 inches above ground level (for drainage). There will be a work bench along the north wall, for working with seedlings, and a full-length raised bed running along the south half of the building, leaving a small path running east-west down the middle (and with a door at each end). I'll have to put in some opening windows for ventilation, and perhaps some screens.
Before it becomes a greenhouse, it will serve as our outdoor kitchen (essentially a roof, under which there is an appropriate area to hang shelving, install a sink, and use a stove, without some leftover room for counter space. It will also have to have a pantry and/or cool box of some kind, but I haven't thought much about it yet. Here is a basic idea of what it will look like as a kitchen, before the cob/strawbales go up, and with a (blue) tarp over the front windows, to keep it cool inside: