A bit more than that.

I copied the following:

Prepar3D v4\Captain_Sim\757-III folder
Prepar3D v4\Captain_Sim\navigation folder
Prepar3D v4\Captain_Sim\bin folder
Prepar3D v4\SimObjects\Airplanes\CS_B757-xxx folders (all entries)
Prepar3D v4\Effects (all cs757_xxx FILE entries (4 cs757_xxx.BMP files are copied from Prepar3D v4\Effects\textures folder))

and pasted them in their relevent folders in Prepar3D v5. I created the Prepar3D v5\Captain_Sim folder before copying those ones over.