Honestly, the best advice for anyone looking to make a load of money is just to buy lots of businesses and rent out lots of properties. Start off in the Dweller Camp and Brightwall and then move up, and buy as many places as often as you can. You can also try to balance out the price of your stores/rent by making some of them high, and some of them low, which wont affect your morality too much. Also, if you ever need to pause the game for a length of time, go to the Road to Rule instead of the Sanctuary, as you still get income there but not in the Sanctuary.