This is so much fun. Thank you for such interesting challenge. Although I'm not a builder/decorator, below is my entry.
A summer house on the beach. Freshly redecorated, yet retains it's charm with original wooden panelling, light colours and thoughtful lighting. Three bedrooms, two and a half bathrooms, kitchen, dining-room and study is included. Exterior features small porch with armchairs, car parking space and modest yard with firepit and etc. Though the house is not the expensive one and room sizes are quite modest, it is enough to enjoy sunny beaches and salty breeze during the summer.
No CC, only EA items from base game and expansions, plus couple of items from the store.
First floor plan. (Study, kitchen with laundry nook, dining-room, living-room and small bathroom);
Second floor plan. (Bedrooms, reading nook by the fireplace and two bathrooms);
Hall on the first floor.
Part of backyard.