Running hot, while driving - 2004 Nissan Titan

Your fan belt should run the entire time your are driving....(if you mean the fan runs the entire time... its ok too).. and your car should not run hot...

I would start by checking the fluid to make sure it's at the proper level, Then check to see if the thermostat is opening like it should. If you have good flow and you get heat inside the car but the car still overheats I think I'd be checking for blown head gaskets and head warp.

Doubt it.
Could be things like an exhaust restriction or flow problem in the block.
You could connect the heater hoses with a piece of pipe to test the theory.

Sounds like you might have a fan problem. Check and make sure the fans are functioning properly.

Most likely a leaky head gasket , the white smoke indicates coolant is getting into combustion chamber/ cylinder(s)

could also indicate a cracked or warped head most often
caused by over heating

For car running hot problem,i suggest you to click this link below and follow the troubleshooting procedure:-----http://technoanswers.blogspot.in/2012/02/car-running-hot.html
-----------Thanks.

Start by flushing your coolant system, then refill with a quality coolant.
Run up to temperature and check again for level (when cool again)

Check that the radiator is getting really hot quite suddenly when running from cold, as this is the best way of checking thermostat operation.
When over a set temperature (check your manual) the fan should come on.
If it never does - troubleshoot the fan (temperature switch or sensor first, then fan on direct feed to see if it powers up ok)

Is the fan running or do you have an electric fan? If fan isnt running or never comes on no matter what you do it will never run much cooler. If fan is good then you could flush the radiator a couple of times and that will help but if fan isnt working it wont last long

need to have the engine block tested or possible bad waterpump

sounds like the radiator is blocked replace it or have it cleaned at a radiator shop