My question would be has this just occurred lately, or always happened with your engine. Most truck engines with a 195 temp T-stat will run at 205 to 210 on the road. When testing engines that have an electric fan with vehicle standing still, the fan switch usually comes on at about 235.
If this is a recent problem, due to age of vehicle I would think either a radiator flush or a new radiator is in order. With age the little cores that feed water across radiator will corrode and restrict flow.