Start up a 2 player FULL game and make sure that your profile chooses the college career path. Then when it's time to choose cards to get a career make sure you get all of them so that you have a better chance of getting doctor as a career choice. If you don't, restart and try again. Furthermore, there is an annoying space that makes you choose a different career path. If you land on this and lose the doctor career, you'll unfortunately have to start over. It's a big pain the ass when that happens but stay persistent! Once you get doctor as a career continue on down the board. At some point, you'll get a chance to buy a second house (you'll obvisouly have to buy one of the starter homes first). Make sure you match all the houses during the mini game and the mansion should be one of your choices. This achievement will unlock as soon as you buy the Mansion. Takes awhile but is not that difficult at all!