What is your Range Rover's GVWR? It should be on your door jamb sticker. Will the empty tow vehicle weight plus
the 590# or more tongue weight plus
humans, gasoline and anything else
inside the tow vehicle exceed the GVWR? A stable tow must bear 10-15% of the trailer gross load on the hitch.
The only way to tell what your vehicle is truly bearing with weight distribution will require that you weigh each axle. You can do this on a trucker's CAT Scale (see this thread
but do a Search -- I recall a number of good how-to posts -- RoadKingMoe and maybe Pick have hashed this one over). It's too bad you can only answer this after you've already bought the trailer.
Look at your Rover's manual for another important number -- the GCWR. How does the combined gassed & peopled tow vehicle and realistic trailer weight stack up against this number?
Ditto on the long trip advice!