I haven't worked much with visitor, so I can't help much there.
Maybe I should give it a look at and see.
With WrpEdit I usually use real world terrain from DEM data, which I then convert to a Lon/Lat Text file for importing into WrpEdit.
I use 3 other programs, Microdem, A DEM to .ter converter and Wilbur, to get the Data into firstly, a suitable Dem, secondly to convert that dem into a Terragen file and lastly to convert the Terragen file into a Lon/Lat text file for importing into WrpEdit.
Maybe I should write another tutorial.
Planck