Hi:
I was in Belfast on March 30 & 31 and took a day trip to (London)Derry on April 1. On March 31 I had Ken Harper pick me up at my hotel, the 30x bombed Europa Hotel, at 9:00 am to do his standard 1-1/2 hour tour of the Falls Road and Shankill Road murals and the Peace Wall. He dropped me off at the Crumlin Road Gaol where I caught the 10:30 tour (though I was booked for 11:00). After the tour I had a leisurely lunch in the gaol cafe, and then headed off to the Titanic museum on foot. Along the way I walked through the cathedral district and saw some wonderful churches. I also stumbled across a Ulster regimental museum and spoke with the curator about the interesting military display. I finally made to the museum and spent about 2-1/2 hours there before leaving. So the answer to your question is: yes, it is possible to do all three in one day if you are in ok condition (I'm in my late 60s). I could not bear to walk back to the hotel so I paid 1 pound 70 pence for the bus ride back. My poor feet thanked me for this.
Let me add: Ken does an excellent tour of both sides of Belfast. You can cover a lot of territory when you have a vehicle. On the 31st I took a walking tour of just Falls Road that was sponsored by Coiste(sp?). This tour was advertised as taking 3 hours but it actually lasted 4-1/2 hours which included a stop at the cematery. We did not see as many murals but saw other things such as an IRA museum and an organization that supports former prisoners. The latter place had, for example, a recreation of a prison cell for women IRA prisoners. The guide himself spent 12 years in prison. Every black cab driver and just about everyone over 50 years old walking on Falls Road knew our guide.
One more comment: on the black cab tour I took many photographs of the murals. On the walking tour the next day one of them had been defaced in the past 24 hours with white paint. The hostility has not ended. The Coiste guide stated that more Peace Wall has been built during the past ten years than all the years since the start of the Troubles.