Built-ins for office. Built ins define an entry via BHG. DIY Built-in IKEA Bookshelves: "Built-in bookcases not only add a ton of character and storage, but they really can make a small house feel so much bigger!
two twin beds. A curtain hung from that cute heading would disguise your "bedroom" if you chose. A curtain would work above as well for either a bed or built in shelves and hanging space for your clothing; I really love the idea of deep, built-in beds