Architect Rocio Romero designs ADUs that are conceived as studios, backyard offices, guest cottages, and short-term getaways. She’s sold over 50 prefab units in 17 different states, and recently launched a series of more modestly sized, construct-it-yourself structures dubbed the Camp series. The 456-square-foot Base Camp and 312-square-foot Fish Camp will both be priced in the $20,000 range. At just over 300 square feet, the Fish Camp is the smaller of the two Camp styles, but the prototype illustrates its utility as guesthouse or office.