What to do with stone outbuilding?

I love your question(s) ! I have so many thoughts for you. Because your main home is a small cottage I would down size all appliances that you can. Minor inconvenience, but this is for a short time if when you anticipate a sale. If you start adding appliances to the outbuilding potential buyers may automatically think you do not have enough space in the cottage and see this as their potential problem. Red Flag, if it is to small for you it may be too small for them. Go the minimalists side! Onto the Stone House: I would play up the Great opportunity with the oddly sized Stone House to the benefit of ever trendy Outside Entertaining. Adding a patio sitting area with many natural elements of plants, garden and herbs before entering the doorway of the stone house to help incoperate the visual idea of an easy flow 'outside to the inside' and vise versa to create the visual idea of additonal space of the open floor plan. Stage it up as a Sitting area for warm nights, possible Arts Studio, work shop. Endless potential and potential to generate additonal monies at sale time. Most importantly without investing excessive amounts of monies into the property that you will eventually sell. Good Luck to you both!