[C#] Multiple Terrains && Loading "Random" Height Maps from Directory

I'm looking to create an arena based game with a few friends. I'm fairly inexperienced with coding in Unity, but I am looking to create a set of 9 tiles of 3 different sizes. Based on the type/size of tile I am looking to load a different type of terrain. The goal of the map will be similar to this:

[table="width: 100, class: grid, align: center"] [tr] [td]2[/td] [td]2[/td] [td]N[/td] [td]1[/td] [td]1[/td] [/tr] [tr] [td]2[/td] [td]2[/td] [td]N[/td] [td]1[/td] [td]1[/td] [/tr] [tr] [td]W[/td] [td]W[/td] [td]C[/td] [td]E[/td] [td]E[/td] [/tr] [tr] [td]3[/td] [td]3[/td] [td]S[/td] [td]4[/td] [td]4[/td] [/tr] [tr] [td]3[/td] [td]3[/td] [td]S[/td] [td]4[/td] [td]4[/td] [/tr] [/table]

Where: [LIST=1] [] Numbers are playable areas [] N,E,S, & W are walls [] C is the impassible center of them map. [/LIST] [B]I'm looking for a way to do the following with C++ Scripts:[/B] [LIST=1] [*] [B]Select & load a HeightMap at "Random" from a directory or folder[/B] [] Rotate a terrain (I assume this is simple, I am just new to this) [/LIST]