SAN DIEGO — At Mitt Romney’s proposed California beach house, the cars will have their own separate elevator. There’s also a planned outdoor shower and a 3,600-square foot basement — a room with more floor space than the existing home’s entire living quarters. Those are just some of the amenities planned for the massive renovation of the Romneys’ home in the tony La Jolla neighborhood of San Diego, according to plans on file with the city. A project this ambitious comes with another feature you don’t always find with the typical fixer-upper: its own lobbyist, hired by Romney to push...