An elderly couple's home and a cozy comfortable home do not necessarily look alike.
When I think of an elderly couple's home, I think of it being somewhat cluttered with outdated curtains and furnishings and old upholstered furniture. Throw in a walker and a cane and hand bars in the bathroom and you have an elderly couple's home.
Comfort need not be synonymous with outdated and old.
Go shopping and buy what YOU like. Paying attention to the scale and proportion of the furnishings for the size of the space you have to decorate. Pick a theme. I know someone who has a lake house and it is decorated with fabrics containing images of ferns and botanicals. The colors are earthy, like the colors found in the fall landscape (green, rust, golden colors, some sage, yellow and rusty reds).
You may want to shop at second hand stores to find items made of wood, iron and colors of nature. Of course you are going to avoid glass table tops with brass legs. A cabin is typically small, so buy furnishings that have multi purposes, keeping in mind that you will need items that double as storage. Buy night stands and end tables that have drawers. Buy a drop leaf table so you can control the size for when company comes over. Maybe select dining chairs that have arms so they can double as extra seating in the living room for extra company. If you only have one bedroom, consider a day bed as a couch for company sleep overs. Or, a pull out couch for guests.
Thrift store shopping will net you some really nice vintage glassware and other kitchen items that will fit well in a cabin kitchen atmosphere.