Hi,
If you hit search and put in Navara or L200 or pick up you will find quite a bit of archive stuff about vanning with pick ups.
The consensus has always been they are OK if this your vehicle of necessity but are not the ideal towcar.
As well as the already mentioned drawbacks of them being seen by some as a commercial vehicle and the possibility of damage to the van because of shock loading there are other worries, such as harsh bouncy ride unless loaded, poor steering lock, lack of interior space and lack of secure stowage.
They certainly look the part though I must admit and certainly with the Navara you are never going to lack for power or traction - a friend we know chain harrows the horse paddock with hers and tows a vast horse box with not a care in the world.