How do you drain the gas tank? Toyoto was running perfect when set up . Now it will barely crank and really runs rough. Could it also be a filter that is stopped up.

As far as draining it the recommended way is to remove the tank. Because of the age of the truck if you tried to drain it by running the fuel pump until empty you risk ruining the pump.
If you can't remember replacing the fuel filter then it's a cheap fix to do regardless of what you end up doing. Always be very careful when working with flamible liquids.

how do you drain the gas tank? Toyoto was running perfect when set up . Now it will barely crank and really runs rough. Could it also be a filter that is stopped up.

Most of them have a drain plug. Make certain that plug isn't stripped or rusted.
Have the drivability problem diagnosed. Fuel condition could be the cause but you may have a dirty carb or faulty ignition components (spark plugs, plug wires, cap and rotor) as well.
If the fuel filter hasn't been replaced in a while, it would probably be a good idea to replace it anyway.