Hong Kong, Macau and Singapore in 4 days. Worth it?

I will be in Beijing for work. And i have 4 days extra for travel. <br><br>I was thinking of going to Hong Kong and Macau. The trip to Hong Kong is around 4 hours. But i have 2 options: <br><br>I can fly from Beijing to Hong Kong and back. But its crazy expensive because the only direct flight (4 hours) is very expensive. But i can go to Shenzhen (the chinese city bordering with Hong Kong) and then by bus can go to Hong Kong. Its a 12 hour trip. But it will be much cheaper (by bus)<br><br>I would like to visit Singapore too. But the flight is 5 hours. <br><br>Is it worth it?